diff --git a/.changeset/fix-jsx-clean-teardown-race.md b/.changeset/fix-jsx-clean-teardown-race.md
deleted file mode 100644
index 750af01a4..000000000
--- a/.changeset/fix-jsx-clean-teardown-race.md
+++ /dev/null
@@ -1,12 +0,0 @@
----
-"@tko/utils.jsx": minor
----
-
-Add `options.jsxCleanBatchSize` (default `1000`) controlling JSX node cleanup
-batching. Setting it to `0` runs cleanup synchronously on detach. Registered
-via `defineOption` — the hardcoded `MAX_CLEAN_AT_ONCE` constant is gone, but
-the new default matches it so production behavior is unchanged.
-
-Fixes a `ReferenceError: Element is not defined` in the `cli-happy-dom` test
-project where the 25ms batch timer could fire after happy-dom had torn down
-DOM globals.
diff --git a/.changeset/fix-proxy-delete-property.md b/.changeset/fix-proxy-delete-property.md
deleted file mode 100644
index 5a56bcccd..000000000
--- a/.changeset/fix-proxy-delete-property.md
+++ /dev/null
@@ -1,18 +0,0 @@
----
-"@tko/computed": patch
----
-
-Fix `ko.proxy` `deleteProperty` trap silently doing nothing
-
-The `deleteProperty` handler on proxies built by `ko.proxy` declared only one
-parameter, named `property`. Per the Proxy spec, the trap is invoked with
-`(target, property)` — so the handler was receiving `target` (the internal
-`function(){}`) in place of the property key, stringifying it, and attempting
-to delete that bogus key. The actual property remained on both the mirror
-observable store and the underlying object, and its tracked observable stayed
-alive.
-
-`delete proxied.foo` now correctly removes `foo` from both the proxy and the
-underlying object and returns `true`. Added a regression test to
-`proxyBehavior.ts` — the bug had been present since `ko.proxy` was introduced
-in 2017 and was untested.
diff --git a/.changeset/modernize-trigger-event.md b/.changeset/modernize-trigger-event.md
deleted file mode 100644
index 594fb790a..000000000
--- a/.changeset/modernize-trigger-event.md
+++ /dev/null
@@ -1,23 +0,0 @@
----
-"@tko/utils": patch
-"@tko/binding.core": patch
-"@tko/provider.component": patch
----
-
-Modernize synthetic event construction
-
-`triggerEvent` (exported from `@tko/utils`) now builds synthetic events using
-`new MouseEvent`/`KeyboardEvent`/`Event` constructors instead of the
-deprecated `document.createEvent('HTMLEvents')` + `initEvent(...)` path. This
-restores native side-effects in modern DOM implementations (e.g. synthetic
-clicks toggle checkbox `.checked` in happy-dom) without changing behavior in
-real browsers. `relatedTarget` is still set to the target element for mouse
-events to match the previous init-event argument list.
-
-`@tko/binding.core` event handler no longer assigns the legacy
-`event.cancelBubble = true` before calling `event.stopPropagation()` — the
-assignment is redundant on modern events and readonly on some implementations.
-
-`@tko/provider.component` now uses `Object.prototype.toString.call(node)` to
-detect `HTMLUnknownElement` rather than `'' + node`, which is immune to
-user-land `toString` overrides on custom elements.
diff --git a/.changeset/modernize-utils-dead-polyfills.md b/.changeset/modernize-utils-dead-polyfills.md
deleted file mode 100644
index 99e1026cf..000000000
--- a/.changeset/modernize-utils-dead-polyfills.md
+++ /dev/null
@@ -1,43 +0,0 @@
----
-"@tko/utils": patch
-"@tko/utils.parser": patch
-"@tko/observable": patch
-"@tko/binding.core": patch
-"@tko/binding.foreach": patch
-"@tko/computed": patch
-"@tko/lifecycle": patch
-"@tko/builder": patch
----
-
-Drop dead polyfill probes from `@tko/utils`
-
-Removes runtime feature detection for capabilities that all supported runtimes
-(modern browsers, Node, Bun, happy-dom) already expose unconditionally. The
-public API surface is preserved as one-line passthroughs in
-`packages/utils/src/compat.ts` so existing consumers continue to work; these
-shims are slated for removal in the next major.
-
-- `functionSupportsLengthOverwrite` + `overwriteLengthPropertyIfSupported` —
-  `Object.defineProperty(fn, 'length', …)` has worked since IE9. Call sites
-  in `@tko/observable` now invoke `Object.defineProperty` directly. The
-  internal probe is gone; `overwriteLengthPropertyIfSupported` is preserved
-  on `@tko/utils` exports as an inline `Object.defineProperty` call.
-- `useSymbols` + `createSymbolOrString` — `Symbol` is always defined; call
-  sites now use `Symbol(identifier)` directly. `createSymbolOrString` is
-  preserved as `s => Symbol(s)` on both `@tko/utils` exports and
-  `ko.utils.createSymbolOrString`.
-- `stringTrim` + `stringStartsWith` — call sites use `String(value ?? '')
-  .trim()` / `value.startsWith(prefix)` inline. Both names remain exported
-  from `@tko/utils` as inline passthroughs.
-- `toggleDomNodeCssClass` SVGAnimatedString fallback — `classList` is
-  available on every supported `Element` (including SVG since SVG2).
-- `parseJson` no longer routes through `stringTrim`; it trims inline when the
-  input is a string.
-
-`packages/utils.parser/src/preparse.ts` also guards `str.match(bindingToken)`
-against the `null` return case using `?? []` — previously relied on the match
-never returning `null` for the transformed input.
-
-Patch-level for all packages: zero observable surface change for consumers
-not reaching into internal probes (`useSymbols`, `functionSupportsLengthOverwrite`),
-which had no monorepo callers.
diff --git a/builds/knockout/CHANGELOG.md b/builds/knockout/CHANGELOG.md
index ec144acf5..e1e9d1ffe 100644
--- a/builds/knockout/CHANGELOG.md
+++ b/builds/knockout/CHANGELOG.md
@@ -1,5 +1,27 @@
 # @tko/build.knockout
 
+## 4.1.0
+
+### Patch Changes
+
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/utils@4.1.0
+  - @tko/binding.core@4.1.0
+  - @tko/provider.component@4.1.0
+  - @tko/binding.foreach@4.1.0
+  - @tko/builder@4.1.0
+  - @tko/binding.component@4.1.0
+  - @tko/binding.if@4.1.0
+  - @tko/binding.template@4.1.0
+  - @tko/filter.punches@4.1.0
+  - @tko/provider.attr@4.1.0
+  - @tko/provider.databind@4.1.0
+  - @tko/provider.multi@4.1.0
+  - @tko/provider.virtual@4.1.0
+  - @tko/utils.component@4.1.0
+  - @tko/utils.functionrewrite@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/builds/knockout/package.json b/builds/knockout/package.json
index f473f1931..eaaff8984 100644
--- a/builds/knockout/package.json
+++ b/builds/knockout/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/build.knockout",
   "description": "Knockout makes it easier to create rich, responsive UIs with JavaScript",
   "homepage": "https://tko.io",
@@ -35,21 +35,21 @@
     }
   ],
   "dependencies": {
-    "@tko/binding.component": "^4.0.1",
-    "@tko/binding.core": "^4.0.1",
-    "@tko/binding.foreach": "^4.0.1",
-    "@tko/binding.if": "^4.0.1",
-    "@tko/binding.template": "^4.0.1",
-    "@tko/builder": "^4.0.1",
-    "@tko/filter.punches": "^4.0.1",
-    "@tko/provider.attr": "^4.0.1",
-    "@tko/provider.component": "^4.0.1",
-    "@tko/provider.databind": "^4.0.1",
-    "@tko/provider.multi": "^4.0.1",
-    "@tko/provider.virtual": "^4.0.1",
-    "@tko/utils.component": "^4.0.1",
-    "@tko/utils.functionrewrite": "^4.0.1",
-    "@tko/utils": "^4.0.1"
+    "@tko/binding.component": "^4.1.0",
+    "@tko/binding.core": "^4.1.0",
+    "@tko/binding.foreach": "^4.1.0",
+    "@tko/binding.if": "^4.1.0",
+    "@tko/binding.template": "^4.1.0",
+    "@tko/builder": "^4.1.0",
+    "@tko/filter.punches": "^4.1.0",
+    "@tko/provider.attr": "^4.1.0",
+    "@tko/provider.component": "^4.1.0",
+    "@tko/provider.databind": "^4.1.0",
+    "@tko/provider.multi": "^4.1.0",
+    "@tko/provider.virtual": "^4.1.0",
+    "@tko/utils.component": "^4.1.0",
+    "@tko/utils.functionrewrite": "^4.1.0",
+    "@tko/utils": "^4.1.0"
   },
   "exports": {
     ".": {
diff --git a/builds/reference/CHANGELOG.md b/builds/reference/CHANGELOG.md
index 6c4cdc916..a5929971f 100644
--- a/builds/reference/CHANGELOG.md
+++ b/builds/reference/CHANGELOG.md
@@ -1,5 +1,30 @@
 # @tko/build.reference
 
+## 4.1.0
+
+### Patch Changes
+
+- Updated dependencies [7938c43]
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/utils.jsx@4.1.0
+  - @tko/utils@4.1.0
+  - @tko/binding.core@4.1.0
+  - @tko/provider.component@4.1.0
+  - @tko/binding.foreach@4.1.0
+  - @tko/builder@4.1.0
+  - @tko/binding.component@4.1.0
+  - @tko/binding.if@4.1.0
+  - @tko/binding.template@4.1.0
+  - @tko/filter.punches@4.1.0
+  - @tko/provider.attr@4.1.0
+  - @tko/provider.databind@4.1.0
+  - @tko/provider.multi@4.1.0
+  - @tko/provider.mustache@4.1.0
+  - @tko/provider.native@4.1.0
+  - @tko/provider.virtual@4.1.0
+  - @tko/utils.component@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/builds/reference/package.json b/builds/reference/package.json
index 472d9b979..a696d4083 100644
--- a/builds/reference/package.json
+++ b/builds/reference/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/build.reference",
   "description": "The TKO Reference Build",
   "repository": {
@@ -9,23 +9,23 @@
   "author": "The Knockout Team",
   "license": "MIT",
   "dependencies": {
-    "@tko/binding.component": "^4.0.1",
-    "@tko/binding.core": "^4.0.1",
-    "@tko/binding.foreach": "^4.0.1",
-    "@tko/binding.if": "^4.0.1",
-    "@tko/binding.template": "^4.0.1",
-    "@tko/builder": "^4.0.1",
-    "@tko/filter.punches": "^4.0.1",
-    "@tko/provider.attr": "^4.0.1",
-    "@tko/provider.component": "^4.0.1",
-    "@tko/provider.databind": "^4.0.1",
-    "@tko/provider.multi": "^4.0.1",
-    "@tko/provider.mustache": "^4.0.1",
-    "@tko/provider.native": "^4.0.1",
-    "@tko/provider.virtual": "^4.0.1",
-    "@tko/utils.component": "^4.0.1",
-    "@tko/utils.jsx": "^4.0.1",
-    "@tko/utils": "^4.0.1"
+    "@tko/binding.component": "^4.1.0",
+    "@tko/binding.core": "^4.1.0",
+    "@tko/binding.foreach": "^4.1.0",
+    "@tko/binding.if": "^4.1.0",
+    "@tko/binding.template": "^4.1.0",
+    "@tko/builder": "^4.1.0",
+    "@tko/filter.punches": "^4.1.0",
+    "@tko/provider.attr": "^4.1.0",
+    "@tko/provider.component": "^4.1.0",
+    "@tko/provider.databind": "^4.1.0",
+    "@tko/provider.multi": "^4.1.0",
+    "@tko/provider.mustache": "^4.1.0",
+    "@tko/provider.native": "^4.1.0",
+    "@tko/provider.virtual": "^4.1.0",
+    "@tko/utils.component": "^4.1.0",
+    "@tko/utils.jsx": "^4.1.0",
+    "@tko/utils": "^4.1.0"
   },
   "files": [
     "dist/"
diff --git a/packages/bind/CHANGELOG.md b/packages/bind/CHANGELOG.md
index 7b1daa9da..01b3e0e2c 100644
--- a/packages/bind/CHANGELOG.md
+++ b/packages/bind/CHANGELOG.md
@@ -1,5 +1,19 @@
 # @tko/bind
 
+## 4.1.0
+
+### Patch Changes
+
+- Updated dependencies [bdac39c]
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/computed@4.1.0
+  - @tko/utils@4.1.0
+  - @tko/observable@4.1.0
+  - @tko/lifecycle@4.1.0
+  - @tko/builder@4.1.0
+  - @tko/provider@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/bind/package.json b/packages/bind/package.json
index 57760e669..435decacb 100644
--- a/packages/bind/package.json
+++ b/packages/bind/package.json
@@ -1,15 +1,15 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/bind",
   "description": "TKO DOM-Observable Binding",
   "module": "dist/index.js",
   "dependencies": {
-    "@tko/computed": "^4.0.1",
-    "@tko/lifecycle": "^4.0.1",
-    "@tko/observable": "^4.0.1",
-    "@tko/provider": "^4.0.1",
-    "@tko/utils": "^4.0.1",
-    "@tko/builder": "^4.0.1"
+    "@tko/computed": "^4.1.0",
+    "@tko/lifecycle": "^4.1.0",
+    "@tko/observable": "^4.1.0",
+    "@tko/provider": "^4.1.0",
+    "@tko/utils": "^4.1.0",
+    "@tko/builder": "^4.1.0"
   },
   "files": [
     "dist/"
diff --git a/packages/binding.component/CHANGELOG.md b/packages/binding.component/CHANGELOG.md
index d0c522156..c75b654ea 100644
--- a/packages/binding.component/CHANGELOG.md
+++ b/packages/binding.component/CHANGELOG.md
@@ -1,5 +1,20 @@
 # @tko/binding.component
 
+## 4.1.0
+
+### Patch Changes
+
+- Updated dependencies [7938c43]
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/utils.jsx@4.1.0
+  - @tko/utils@4.1.0
+  - @tko/observable@4.1.0
+  - @tko/lifecycle@4.1.0
+  - @tko/bind@4.1.0
+  - @tko/provider.native@4.1.0
+  - @tko/utils.component@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/binding.component/package.json b/packages/binding.component/package.json
index 1c38636dd..f94c23c30 100644
--- a/packages/binding.component/package.json
+++ b/packages/binding.component/package.json
@@ -1,17 +1,17 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/binding.component",
   "description": "component: binding for web components",
   "module": "dist/index.js",
   "license": "MIT",
   "dependencies": {
-    "@tko/bind": "^4.0.1",
-    "@tko/lifecycle": "^4.0.1",
-    "@tko/observable": "^4.0.1",
-    "@tko/provider.native": "^4.0.1",
-    "@tko/utils": "^4.0.1",
-    "@tko/utils.component": "^4.0.1",
-    "@tko/utils.jsx": "^4.0.1"
+    "@tko/bind": "^4.1.0",
+    "@tko/lifecycle": "^4.1.0",
+    "@tko/observable": "^4.1.0",
+    "@tko/provider.native": "^4.1.0",
+    "@tko/utils": "^4.1.0",
+    "@tko/utils.component": "^4.1.0",
+    "@tko/utils.jsx": "^4.1.0"
   },
   "files": [
     "dist/"
diff --git a/packages/binding.core/CHANGELOG.md b/packages/binding.core/CHANGELOG.md
index b8e3d8f68..cf0e87e79 100644
--- a/packages/binding.core/CHANGELOG.md
+++ b/packages/binding.core/CHANGELOG.md
@@ -1,5 +1,68 @@
 # @tko/binding.core
 
+## 4.1.0
+
+### Patch Changes
+
+- 3aea21c: Modernize synthetic event construction
+
+  `triggerEvent` (exported from `@tko/utils`) now builds synthetic events using
+  `new MouseEvent`/`KeyboardEvent`/`Event` constructors instead of the
+  deprecated `document.createEvent('HTMLEvents')` + `initEvent(...)` path. This
+  restores native side-effects in modern DOM implementations (e.g. synthetic
+  clicks toggle checkbox `.checked` in happy-dom) without changing behavior in
+  real browsers. `relatedTarget` is still set to the target element for mouse
+  events to match the previous init-event argument list.
+
+  `@tko/binding.core` event handler no longer assigns the legacy
+  `event.cancelBubble = true` before calling `event.stopPropagation()` — the
+  assignment is redundant on modern events and readonly on some implementations.
+
+  `@tko/provider.component` now uses `Object.prototype.toString.call(node)` to
+  detect `HTMLUnknownElement` rather than `'' + node`, which is immune to
+  user-land `toString` overrides on custom elements.
+
+- 49576cb: Drop dead polyfill probes from `@tko/utils`
+
+  Removes runtime feature detection for capabilities that all supported runtimes
+  (modern browsers, Node, Bun, happy-dom) already expose unconditionally. The
+  public API surface is preserved as one-line passthroughs in
+  `packages/utils/src/compat.ts` so existing consumers continue to work; these
+  shims are slated for removal in the next major.
+
+  - `functionSupportsLengthOverwrite` + `overwriteLengthPropertyIfSupported` —
+    `Object.defineProperty(fn, 'length', …)` has worked since IE9. Call sites
+    in `@tko/observable` now invoke `Object.defineProperty` directly. The
+    internal probe is gone; `overwriteLengthPropertyIfSupported` is preserved
+    on `@tko/utils` exports as an inline `Object.defineProperty` call.
+  - `useSymbols` + `createSymbolOrString` — `Symbol` is always defined; call
+    sites now use `Symbol(identifier)` directly. `createSymbolOrString` is
+    preserved as `s => Symbol(s)` on both `@tko/utils` exports and
+    `ko.utils.createSymbolOrString`.
+  - `stringTrim` + `stringStartsWith` — call sites use `String(value ?? '')
+.trim()` / `value.startsWith(prefix)` inline. Both names remain exported
+    from `@tko/utils` as inline passthroughs.
+  - `toggleDomNodeCssClass` SVGAnimatedString fallback — `classList` is
+    available on every supported `Element` (including SVG since SVG2).
+  - `parseJson` no longer routes through `stringTrim`; it trims inline when the
+    input is a string.
+
+  `packages/utils.parser/src/preparse.ts` also guards `str.match(bindingToken)`
+  against the `null` return case using `?? []` — previously relied on the match
+  never returning `null` for the transformed input.
+
+  Patch-level for all packages: zero observable surface change for consumers
+  not reaching into internal probes (`useSymbols`, `functionSupportsLengthOverwrite`),
+  which had no monorepo callers.
+
+- Updated dependencies [bdac39c]
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/computed@4.1.0
+  - @tko/utils@4.1.0
+  - @tko/observable@4.1.0
+  - @tko/bind@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/binding.core/package.json b/packages/binding.core/package.json
index a5b473395..fef66bb15 100644
--- a/packages/binding.core/package.json
+++ b/packages/binding.core/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/binding.core",
   "description": "TKO Core bindings",
   "module": "dist/index.js",
@@ -24,10 +24,10 @@
   },
   "homepage": "https://tko.io",
   "dependencies": {
-    "@tko/bind": "^4.0.1",
-    "@tko/computed": "^4.0.1",
-    "@tko/observable": "^4.0.1",
-    "@tko/utils": "^4.0.1"
+    "@tko/bind": "^4.1.0",
+    "@tko/computed": "^4.1.0",
+    "@tko/observable": "^4.1.0",
+    "@tko/utils": "^4.1.0"
   },
   "licenses": [
     {
diff --git a/packages/binding.foreach/CHANGELOG.md b/packages/binding.foreach/CHANGELOG.md
index c25ef8296..908329933 100644
--- a/packages/binding.foreach/CHANGELOG.md
+++ b/packages/binding.foreach/CHANGELOG.md
@@ -1,5 +1,48 @@
 # @tko/binding.foreach
 
+## 4.1.0
+
+### Patch Changes
+
+- 49576cb: Drop dead polyfill probes from `@tko/utils`
+
+  Removes runtime feature detection for capabilities that all supported runtimes
+  (modern browsers, Node, Bun, happy-dom) already expose unconditionally. The
+  public API surface is preserved as one-line passthroughs in
+  `packages/utils/src/compat.ts` so existing consumers continue to work; these
+  shims are slated for removal in the next major.
+
+  - `functionSupportsLengthOverwrite` + `overwriteLengthPropertyIfSupported` —
+    `Object.defineProperty(fn, 'length', …)` has worked since IE9. Call sites
+    in `@tko/observable` now invoke `Object.defineProperty` directly. The
+    internal probe is gone; `overwriteLengthPropertyIfSupported` is preserved
+    on `@tko/utils` exports as an inline `Object.defineProperty` call.
+  - `useSymbols` + `createSymbolOrString` — `Symbol` is always defined; call
+    sites now use `Symbol(identifier)` directly. `createSymbolOrString` is
+    preserved as `s => Symbol(s)` on both `@tko/utils` exports and
+    `ko.utils.createSymbolOrString`.
+  - `stringTrim` + `stringStartsWith` — call sites use `String(value ?? '')
+.trim()` / `value.startsWith(prefix)` inline. Both names remain exported
+    from `@tko/utils` as inline passthroughs.
+  - `toggleDomNodeCssClass` SVGAnimatedString fallback — `classList` is
+    available on every supported `Element` (including SVG since SVG2).
+  - `parseJson` no longer routes through `stringTrim`; it trims inline when the
+    input is a string.
+
+  `packages/utils.parser/src/preparse.ts` also guards `str.match(bindingToken)`
+  against the `null` return case using `?? []` — previously relied on the match
+  never returning `null` for the transformed input.
+
+  Patch-level for all packages: zero observable surface change for consumers
+  not reaching into internal probes (`useSymbols`, `functionSupportsLengthOverwrite`),
+  which had no monorepo callers.
+
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/utils@4.1.0
+  - @tko/observable@4.1.0
+  - @tko/bind@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/binding.foreach/package.json b/packages/binding.foreach/package.json
index 3a7724f31..ee50c181a 100644
--- a/packages/binding.foreach/package.json
+++ b/packages/binding.foreach/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/binding.foreach",
   "description": "Knockout Foreach Binding",
   "module": "dist/index.js",
@@ -24,9 +24,9 @@
   },
   "homepage": "https://tko.io",
   "dependencies": {
-    "@tko/bind": "^4.0.1",
-    "@tko/observable": "^4.0.1",
-    "@tko/utils": "^4.0.1"
+    "@tko/bind": "^4.1.0",
+    "@tko/observable": "^4.1.0",
+    "@tko/utils": "^4.1.0"
   },
   "licenses": [
     {
diff --git a/packages/binding.if/CHANGELOG.md b/packages/binding.if/CHANGELOG.md
index 1f746be50..a4d953ef5 100644
--- a/packages/binding.if/CHANGELOG.md
+++ b/packages/binding.if/CHANGELOG.md
@@ -1,5 +1,15 @@
 # @tko/binding.if
 
+## 4.1.0
+
+### Patch Changes
+
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/utils@4.1.0
+  - @tko/observable@4.1.0
+  - @tko/bind@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/binding.if/package.json b/packages/binding.if/package.json
index 15f9bb7de..c40bb1d0d 100644
--- a/packages/binding.if/package.json
+++ b/packages/binding.if/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/binding.if",
   "description": "TKO conditional (if/ifnot/unless/with/else) bindings",
   "module": "dist/index.js",
@@ -24,9 +24,9 @@
   },
   "homepage": "https://tko.io",
   "dependencies": {
-    "@tko/bind": "^4.0.1",
-    "@tko/observable": "^4.0.1",
-    "@tko/utils": "^4.0.1"
+    "@tko/bind": "^4.1.0",
+    "@tko/observable": "^4.1.0",
+    "@tko/utils": "^4.1.0"
   },
   "licenses": [
     {
diff --git a/packages/binding.template/CHANGELOG.md b/packages/binding.template/CHANGELOG.md
index e80fa9a04..86295ae07 100644
--- a/packages/binding.template/CHANGELOG.md
+++ b/packages/binding.template/CHANGELOG.md
@@ -1,5 +1,17 @@
 # @tko/binding.template
 
+## 4.1.0
+
+### Patch Changes
+
+- Updated dependencies [bdac39c]
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/computed@4.1.0
+  - @tko/utils@4.1.0
+  - @tko/observable@4.1.0
+  - @tko/bind@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/binding.template/package.json b/packages/binding.template/package.json
index 62c735911..36e247054 100644
--- a/packages/binding.template/package.json
+++ b/packages/binding.template/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/binding.template",
   "description": "TKO Template bindings",
   "module": "dist/index.js",
@@ -24,10 +24,10 @@
   },
   "homepage": "https://tko.io",
   "dependencies": {
-    "@tko/bind": "^4.0.1",
-    "@tko/computed": "^4.0.1",
-    "@tko/observable": "^4.0.1",
-    "@tko/utils": "^4.0.1"
+    "@tko/bind": "^4.1.0",
+    "@tko/computed": "^4.1.0",
+    "@tko/observable": "^4.1.0",
+    "@tko/utils": "^4.1.0"
   },
   "licenses": [
     {
diff --git a/packages/builder/CHANGELOG.md b/packages/builder/CHANGELOG.md
index edc17f3ad..17aabe1c1 100644
--- a/packages/builder/CHANGELOG.md
+++ b/packages/builder/CHANGELOG.md
@@ -1,5 +1,54 @@
 # @tko/builder
 
+## 4.1.0
+
+### Patch Changes
+
+- 49576cb: Drop dead polyfill probes from `@tko/utils`
+
+  Removes runtime feature detection for capabilities that all supported runtimes
+  (modern browsers, Node, Bun, happy-dom) already expose unconditionally. The
+  public API surface is preserved as one-line passthroughs in
+  `packages/utils/src/compat.ts` so existing consumers continue to work; these
+  shims are slated for removal in the next major.
+
+  - `functionSupportsLengthOverwrite` + `overwriteLengthPropertyIfSupported` —
+    `Object.defineProperty(fn, 'length', …)` has worked since IE9. Call sites
+    in `@tko/observable` now invoke `Object.defineProperty` directly. The
+    internal probe is gone; `overwriteLengthPropertyIfSupported` is preserved
+    on `@tko/utils` exports as an inline `Object.defineProperty` call.
+  - `useSymbols` + `createSymbolOrString` — `Symbol` is always defined; call
+    sites now use `Symbol(identifier)` directly. `createSymbolOrString` is
+    preserved as `s => Symbol(s)` on both `@tko/utils` exports and
+    `ko.utils.createSymbolOrString`.
+  - `stringTrim` + `stringStartsWith` — call sites use `String(value ?? '')
+.trim()` / `value.startsWith(prefix)` inline. Both names remain exported
+    from `@tko/utils` as inline passthroughs.
+  - `toggleDomNodeCssClass` SVGAnimatedString fallback — `classList` is
+    available on every supported `Element` (including SVG since SVG2).
+  - `parseJson` no longer routes through `stringTrim`; it trims inline when the
+    input is a string.
+
+  `packages/utils.parser/src/preparse.ts` also guards `str.match(bindingToken)`
+  against the `null` return case using `?? []` — previously relied on the match
+  never returning `null` for the transformed input.
+
+  Patch-level for all packages: zero observable surface change for consumers
+  not reaching into internal probes (`useSymbols`, `functionSupportsLengthOverwrite`),
+  which had no monorepo callers.
+
+- Updated dependencies [bdac39c]
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/computed@4.1.0
+  - @tko/utils@4.1.0
+  - @tko/utils.parser@4.1.0
+  - @tko/observable@4.1.0
+  - @tko/lifecycle@4.1.0
+  - @tko/bind@4.1.0
+  - @tko/binding.template@4.1.0
+  - @tko/provider@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/builder/package.json b/packages/builder/package.json
index bf335d9ae..105de0015 100644
--- a/packages/builder/package.json
+++ b/packages/builder/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/builder",
   "description": "Compile a customized instance of Knockout.",
   "repository": {
@@ -9,14 +9,14 @@
   "author": "The Knockout Team",
   "license": "MIT",
   "dependencies": {
-    "@tko/bind": "^4.0.1",
-    "@tko/binding.template": "^4.0.1",
-    "@tko/computed": "^4.0.1",
-    "@tko/lifecycle": "^4.0.1",
-    "@tko/observable": "^4.0.1",
-    "@tko/provider": "^4.0.1",
-    "@tko/utils": "^4.0.1",
-    "@tko/utils.parser": "^4.0.1"
+    "@tko/bind": "^4.1.0",
+    "@tko/binding.template": "^4.1.0",
+    "@tko/computed": "^4.1.0",
+    "@tko/lifecycle": "^4.1.0",
+    "@tko/observable": "^4.1.0",
+    "@tko/provider": "^4.1.0",
+    "@tko/utils": "^4.1.0",
+    "@tko/utils.parser": "^4.1.0"
   },
   "homepage": "https://tko.io",
   "licenses": [
diff --git a/packages/computed/CHANGELOG.md b/packages/computed/CHANGELOG.md
index 9b00ee851..2a46c1640 100644
--- a/packages/computed/CHANGELOG.md
+++ b/packages/computed/CHANGELOG.md
@@ -1,5 +1,62 @@
 # @tko/computed
 
+## 4.1.0
+
+### Patch Changes
+
+- bdac39c: Fix `ko.proxy` `deleteProperty` trap silently doing nothing
+
+  The `deleteProperty` handler on proxies built by `ko.proxy` declared only one
+  parameter, named `property`. Per the Proxy spec, the trap is invoked with
+  `(target, property)` — so the handler was receiving `target` (the internal
+  `function(){}`) in place of the property key, stringifying it, and attempting
+  to delete that bogus key. The actual property remained on both the mirror
+  observable store and the underlying object, and its tracked observable stayed
+  alive.
+
+  `delete proxied.foo` now correctly removes `foo` from both the proxy and the
+  underlying object and returns `true`. Added a regression test to
+  `proxyBehavior.ts` — the bug had been present since `ko.proxy` was introduced
+  in 2017 and was untested.
+
+- 49576cb: Drop dead polyfill probes from `@tko/utils`
+
+  Removes runtime feature detection for capabilities that all supported runtimes
+  (modern browsers, Node, Bun, happy-dom) already expose unconditionally. The
+  public API surface is preserved as one-line passthroughs in
+  `packages/utils/src/compat.ts` so existing consumers continue to work; these
+  shims are slated for removal in the next major.
+
+  - `functionSupportsLengthOverwrite` + `overwriteLengthPropertyIfSupported` —
+    `Object.defineProperty(fn, 'length', …)` has worked since IE9. Call sites
+    in `@tko/observable` now invoke `Object.defineProperty` directly. The
+    internal probe is gone; `overwriteLengthPropertyIfSupported` is preserved
+    on `@tko/utils` exports as an inline `Object.defineProperty` call.
+  - `useSymbols` + `createSymbolOrString` — `Symbol` is always defined; call
+    sites now use `Symbol(identifier)` directly. `createSymbolOrString` is
+    preserved as `s => Symbol(s)` on both `@tko/utils` exports and
+    `ko.utils.createSymbolOrString`.
+  - `stringTrim` + `stringStartsWith` — call sites use `String(value ?? '')
+.trim()` / `value.startsWith(prefix)` inline. Both names remain exported
+    from `@tko/utils` as inline passthroughs.
+  - `toggleDomNodeCssClass` SVGAnimatedString fallback — `classList` is
+    available on every supported `Element` (including SVG since SVG2).
+  - `parseJson` no longer routes through `stringTrim`; it trims inline when the
+    input is a string.
+
+  `packages/utils.parser/src/preparse.ts` also guards `str.match(bindingToken)`
+  against the `null` return case using `?? []` — previously relied on the match
+  never returning `null` for the transformed input.
+
+  Patch-level for all packages: zero observable surface change for consumers
+  not reaching into internal probes (`useSymbols`, `functionSupportsLengthOverwrite`),
+  which had no monorepo callers.
+
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/utils@4.1.0
+  - @tko/observable@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/computed/package.json b/packages/computed/package.json
index f2793d545..8043196be 100644
--- a/packages/computed/package.json
+++ b/packages/computed/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/computed",
   "description": "TKO Computed Observables",
   "module": "dist/index.js",
@@ -7,8 +7,8 @@
     "dist/"
   ],
   "dependencies": {
-    "@tko/observable": "^4.0.1",
-    "@tko/utils": "^4.0.1"
+    "@tko/observable": "^4.1.0",
+    "@tko/utils": "^4.1.0"
   },
   "repository": {
     "type": "git",
diff --git a/packages/filter.punches/CHANGELOG.md b/packages/filter.punches/CHANGELOG.md
index 336ba1522..644950a2e 100644
--- a/packages/filter.punches/CHANGELOG.md
+++ b/packages/filter.punches/CHANGELOG.md
@@ -1,5 +1,12 @@
 # @tko/filter.punches
 
+## 4.1.0
+
+### Patch Changes
+
+- Updated dependencies [49576cb]
+  - @tko/observable@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/filter.punches/package.json b/packages/filter.punches/package.json
index b8a4ee226..1247b1224 100644
--- a/packages/filter.punches/package.json
+++ b/packages/filter.punches/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/filter.punches",
   "description": "TKO filters from knockout punches",
   "module": "dist/index.js",
@@ -24,7 +24,7 @@
   },
   "homepage": "https://tko.io",
   "dependencies": {
-    "@tko/observable": "^4.0.1"
+    "@tko/observable": "^4.1.0"
   },
   "licenses": [
     {
diff --git a/packages/lifecycle/CHANGELOG.md b/packages/lifecycle/CHANGELOG.md
index 91cd820be..8e17aa107 100644
--- a/packages/lifecycle/CHANGELOG.md
+++ b/packages/lifecycle/CHANGELOG.md
@@ -1,5 +1,49 @@
 # @tko/lifecycle
 
+## 4.1.0
+
+### Patch Changes
+
+- 49576cb: Drop dead polyfill probes from `@tko/utils`
+
+  Removes runtime feature detection for capabilities that all supported runtimes
+  (modern browsers, Node, Bun, happy-dom) already expose unconditionally. The
+  public API surface is preserved as one-line passthroughs in
+  `packages/utils/src/compat.ts` so existing consumers continue to work; these
+  shims are slated for removal in the next major.
+
+  - `functionSupportsLengthOverwrite` + `overwriteLengthPropertyIfSupported` —
+    `Object.defineProperty(fn, 'length', …)` has worked since IE9. Call sites
+    in `@tko/observable` now invoke `Object.defineProperty` directly. The
+    internal probe is gone; `overwriteLengthPropertyIfSupported` is preserved
+    on `@tko/utils` exports as an inline `Object.defineProperty` call.
+  - `useSymbols` + `createSymbolOrString` — `Symbol` is always defined; call
+    sites now use `Symbol(identifier)` directly. `createSymbolOrString` is
+    preserved as `s => Symbol(s)` on both `@tko/utils` exports and
+    `ko.utils.createSymbolOrString`.
+  - `stringTrim` + `stringStartsWith` — call sites use `String(value ?? '')
+.trim()` / `value.startsWith(prefix)` inline. Both names remain exported
+    from `@tko/utils` as inline passthroughs.
+  - `toggleDomNodeCssClass` SVGAnimatedString fallback — `classList` is
+    available on every supported `Element` (including SVG since SVG2).
+  - `parseJson` no longer routes through `stringTrim`; it trims inline when the
+    input is a string.
+
+  `packages/utils.parser/src/preparse.ts` also guards `str.match(bindingToken)`
+  against the `null` return case using `?? []` — previously relied on the match
+  never returning `null` for the transformed input.
+
+  Patch-level for all packages: zero observable surface change for consumers
+  not reaching into internal probes (`useSymbols`, `functionSupportsLengthOverwrite`),
+  which had no monorepo callers.
+
+- Updated dependencies [bdac39c]
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/computed@4.1.0
+  - @tko/utils@4.1.0
+  - @tko/observable@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/lifecycle/package.json b/packages/lifecycle/package.json
index 8afc1b335..2c7a583ee 100644
--- a/packages/lifecycle/package.json
+++ b/packages/lifecycle/package.json
@@ -1,10 +1,10 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "module": "dist/index.js",
   "dependencies": {
-    "@tko/computed": "^4.0.1",
-    "@tko/observable": "^4.0.1",
-    "@tko/utils": "^4.0.1"
+    "@tko/computed": "^4.1.0",
+    "@tko/observable": "^4.1.0",
+    "@tko/utils": "^4.1.0"
   },
   "files": [
     "dist/"
diff --git a/packages/observable/CHANGELOG.md b/packages/observable/CHANGELOG.md
index 42bca0dbe..4bd6be414 100644
--- a/packages/observable/CHANGELOG.md
+++ b/packages/observable/CHANGELOG.md
@@ -1,5 +1,46 @@
 # @tko/observable
 
+## 4.1.0
+
+### Patch Changes
+
+- 49576cb: Drop dead polyfill probes from `@tko/utils`
+
+  Removes runtime feature detection for capabilities that all supported runtimes
+  (modern browsers, Node, Bun, happy-dom) already expose unconditionally. The
+  public API surface is preserved as one-line passthroughs in
+  `packages/utils/src/compat.ts` so existing consumers continue to work; these
+  shims are slated for removal in the next major.
+
+  - `functionSupportsLengthOverwrite` + `overwriteLengthPropertyIfSupported` —
+    `Object.defineProperty(fn, 'length', …)` has worked since IE9. Call sites
+    in `@tko/observable` now invoke `Object.defineProperty` directly. The
+    internal probe is gone; `overwriteLengthPropertyIfSupported` is preserved
+    on `@tko/utils` exports as an inline `Object.defineProperty` call.
+  - `useSymbols` + `createSymbolOrString` — `Symbol` is always defined; call
+    sites now use `Symbol(identifier)` directly. `createSymbolOrString` is
+    preserved as `s => Symbol(s)` on both `@tko/utils` exports and
+    `ko.utils.createSymbolOrString`.
+  - `stringTrim` + `stringStartsWith` — call sites use `String(value ?? '')
+.trim()` / `value.startsWith(prefix)` inline. Both names remain exported
+    from `@tko/utils` as inline passthroughs.
+  - `toggleDomNodeCssClass` SVGAnimatedString fallback — `classList` is
+    available on every supported `Element` (including SVG since SVG2).
+  - `parseJson` no longer routes through `stringTrim`; it trims inline when the
+    input is a string.
+
+  `packages/utils.parser/src/preparse.ts` also guards `str.match(bindingToken)`
+  against the `null` return case using `?? []` — previously relied on the match
+  never returning `null` for the transformed input.
+
+  Patch-level for all packages: zero observable surface change for consumers
+  not reaching into internal probes (`useSymbols`, `functionSupportsLengthOverwrite`),
+  which had no monorepo callers.
+
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/utils@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/observable/package.json b/packages/observable/package.json
index c8ad7cf0b..6926ade7d 100644
--- a/packages/observable/package.json
+++ b/packages/observable/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/observable",
   "description": "TKO subscribables and observables",
   "repository": {
@@ -29,7 +29,7 @@
   },
   "homepage": "https://tko.io",
   "dependencies": {
-    "@tko/utils": "^4.0.1"
+    "@tko/utils": "^4.1.0"
   },
   "licenses": [
     {
diff --git a/packages/provider.attr/CHANGELOG.md b/packages/provider.attr/CHANGELOG.md
index d3337f8a2..47d7fd356 100644
--- a/packages/provider.attr/CHANGELOG.md
+++ b/packages/provider.attr/CHANGELOG.md
@@ -1,5 +1,11 @@
 # @tko/provider.attr
 
+## 4.1.0
+
+### Patch Changes
+
+- @tko/provider@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/provider.attr/package.json b/packages/provider.attr/package.json
index 9b01d39fd..afc7a813b 100644
--- a/packages/provider.attr/package.json
+++ b/packages/provider.attr/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/provider.attr",
   "description": "Link HTML attributes (e.g. ko-handler-name) to binding handlers",
   "module": "dist/index.js",
@@ -8,7 +8,7 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@tko/provider": "^4.0.1"
+    "@tko/provider": "^4.1.0"
   },
   "homepage": "https://tko.io",
   "licenses": [
diff --git a/packages/provider.bindingstring/CHANGELOG.md b/packages/provider.bindingstring/CHANGELOG.md
index 635550d09..bd388f6e1 100644
--- a/packages/provider.bindingstring/CHANGELOG.md
+++ b/packages/provider.bindingstring/CHANGELOG.md
@@ -1,5 +1,13 @@
 # @tko/provider.bindingstring
 
+## 4.1.0
+
+### Patch Changes
+
+- Updated dependencies [49576cb]
+  - @tko/utils.parser@4.1.0
+  - @tko/provider@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/provider.bindingstring/package.json b/packages/provider.bindingstring/package.json
index 0b11619f9..24aa53651 100644
--- a/packages/provider.bindingstring/package.json
+++ b/packages/provider.bindingstring/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/provider.bindingstring",
   "description": "Abstract Base Class for providers that parse a binding string",
   "module": "dist/index.js",
@@ -8,8 +8,8 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@tko/provider": "^4.0.1",
-    "@tko/utils.parser": "^4.0.1"
+    "@tko/provider": "^4.1.0",
+    "@tko/utils.parser": "^4.1.0"
   },
   "homepage": "https://tko.io",
   "licenses": [
diff --git a/packages/provider.component/CHANGELOG.md b/packages/provider.component/CHANGELOG.md
index 8d6fb6113..f5af0dd18 100644
--- a/packages/provider.component/CHANGELOG.md
+++ b/packages/provider.component/CHANGELOG.md
@@ -1,5 +1,37 @@
 # @tko/provider.component
 
+## 4.1.0
+
+### Patch Changes
+
+- 3aea21c: Modernize synthetic event construction
+
+  `triggerEvent` (exported from `@tko/utils`) now builds synthetic events using
+  `new MouseEvent`/`KeyboardEvent`/`Event` constructors instead of the
+  deprecated `document.createEvent('HTMLEvents')` + `initEvent(...)` path. This
+  restores native side-effects in modern DOM implementations (e.g. synthetic
+  clicks toggle checkbox `.checked` in happy-dom) without changing behavior in
+  real browsers. `relatedTarget` is still set to the target element for mouse
+  events to match the previous init-event argument list.
+
+  `@tko/binding.core` event handler no longer assigns the legacy
+  `event.cancelBubble = true` before calling `event.stopPropagation()` — the
+  assignment is redundant on modern events and readonly on some implementations.
+
+  `@tko/provider.component` now uses `Object.prototype.toString.call(node)` to
+  detect `HTMLUnknownElement` rather than `'' + node`, which is immune to
+  user-land `toString` overrides on custom elements.
+
+- Updated dependencies [bdac39c]
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/computed@4.1.0
+  - @tko/utils@4.1.0
+  - @tko/utils.parser@4.1.0
+  - @tko/observable@4.1.0
+  - @tko/provider@4.1.0
+  - @tko/utils.component@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/provider.component/package.json b/packages/provider.component/package.json
index 27e071fa9..fe5ca559b 100644
--- a/packages/provider.component/package.json
+++ b/packages/provider.component/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/provider.component",
   "description": "Bind custom web components e.g. <custom-binding>",
   "module": "dist/index.js",
@@ -8,12 +8,12 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@tko/computed": "^4.0.1",
-    "@tko/observable": "^4.0.1",
-    "@tko/provider": "^4.0.1",
-    "@tko/utils": "^4.0.1",
-    "@tko/utils.component": "^4.0.1",
-    "@tko/utils.parser": "^4.0.1"
+    "@tko/computed": "^4.1.0",
+    "@tko/observable": "^4.1.0",
+    "@tko/provider": "^4.1.0",
+    "@tko/utils": "^4.1.0",
+    "@tko/utils.component": "^4.1.0",
+    "@tko/utils.parser": "^4.1.0"
   },
   "homepage": "https://tko.io",
   "licenses": [
diff --git a/packages/provider.databind/CHANGELOG.md b/packages/provider.databind/CHANGELOG.md
index 81c0b3225..015daca26 100644
--- a/packages/provider.databind/CHANGELOG.md
+++ b/packages/provider.databind/CHANGELOG.md
@@ -1,5 +1,12 @@
 # @tko/provider.databind
 
+## 4.1.0
+
+### Patch Changes
+
+- @tko/bind@4.1.0
+- @tko/provider.bindingstring@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/provider.databind/package.json b/packages/provider.databind/package.json
index 2a5f5f5d8..52b3b5377 100644
--- a/packages/provider.databind/package.json
+++ b/packages/provider.databind/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/provider.databind",
   "description": "Link HTML attributes based on a `data-bind` HTML attribute",
   "module": "dist/index.js",
@@ -8,8 +8,8 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@tko/provider.bindingstring": "^4.0.1",
-    "@tko/bind": "^4.0.1"
+    "@tko/provider.bindingstring": "^4.1.0",
+    "@tko/bind": "^4.1.0"
   },
   "homepage": "https://tko.io",
   "licenses": [
diff --git a/packages/provider.multi/CHANGELOG.md b/packages/provider.multi/CHANGELOG.md
index 8f0431fe6..92ffdf496 100644
--- a/packages/provider.multi/CHANGELOG.md
+++ b/packages/provider.multi/CHANGELOG.md
@@ -1,5 +1,12 @@
 # @tko/provider.multi
 
+## 4.1.0
+
+### Patch Changes
+
+- @tko/bind@4.1.0
+- @tko/provider@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/provider.multi/package.json b/packages/provider.multi/package.json
index ab2881bcf..9f1066d3e 100644
--- a/packages/provider.multi/package.json
+++ b/packages/provider.multi/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/provider.multi",
   "description": "Combine multiple other providers into one",
   "module": "dist/index.js",
@@ -8,8 +8,8 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@tko/provider": "^4.0.1",
-    "@tko/bind": "^4.0.1"
+    "@tko/provider": "^4.1.0",
+    "@tko/bind": "^4.1.0"
   },
   "homepage": "https://tko.io",
   "licenses": [
diff --git a/packages/provider.mustache/CHANGELOG.md b/packages/provider.mustache/CHANGELOG.md
index a4fc8d9bc..c6334dc9b 100644
--- a/packages/provider.mustache/CHANGELOG.md
+++ b/packages/provider.mustache/CHANGELOG.md
@@ -1,5 +1,14 @@
 # @tko/provider.mustache
 
+## 4.1.0
+
+### Patch Changes
+
+- Updated dependencies [49576cb]
+  - @tko/utils.parser@4.1.0
+  - @tko/observable@4.1.0
+  - @tko/provider@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/provider.mustache/package.json b/packages/provider.mustache/package.json
index 899c2a630..c2198e39a 100644
--- a/packages/provider.mustache/package.json
+++ b/packages/provider.mustache/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/provider.mustache",
   "description": "Interpolate text/node attributes {{ }}",
   "module": "dist/index.js",
@@ -24,9 +24,9 @@
   },
   "homepage": "https://tko.io",
   "dependencies": {
-    "@tko/observable": "^4.0.1",
-    "@tko/provider": "^4.0.1",
-    "@tko/utils.parser": "^4.0.1"
+    "@tko/observable": "^4.1.0",
+    "@tko/provider": "^4.1.0",
+    "@tko/utils.parser": "^4.1.0"
   },
   "licenses": [
     {
diff --git a/packages/provider.native/CHANGELOG.md b/packages/provider.native/CHANGELOG.md
index dfe81f284..9cce11fcb 100644
--- a/packages/provider.native/CHANGELOG.md
+++ b/packages/provider.native/CHANGELOG.md
@@ -1,5 +1,14 @@
 # @tko/provider.native
 
+## 4.1.0
+
+### Patch Changes
+
+- Updated dependencies [49576cb]
+  - @tko/observable@4.1.0
+  - @tko/bind@4.1.0
+  - @tko/provider@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/provider.native/package.json b/packages/provider.native/package.json
index f6189cb76..d204b0154 100644
--- a/packages/provider.native/package.json
+++ b/packages/provider.native/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/provider.native",
   "description": "Link binding handlers whose value is already attached to the node",
   "module": "dist/index.js",
@@ -8,9 +8,9 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@tko/observable": "^4.0.1",
-    "@tko/provider": "^4.0.1",
-    "@tko/bind": "^4.0.1"
+    "@tko/observable": "^4.1.0",
+    "@tko/provider": "^4.1.0",
+    "@tko/bind": "^4.1.0"
   },
   "homepage": "https://tko.io",
   "licenses": [
diff --git a/packages/provider.virtual/CHANGELOG.md b/packages/provider.virtual/CHANGELOG.md
index 961dd74db..1039565bd 100644
--- a/packages/provider.virtual/CHANGELOG.md
+++ b/packages/provider.virtual/CHANGELOG.md
@@ -1,5 +1,15 @@
 # @tko/provider.virtual
 
+## 4.1.0
+
+### Patch Changes
+
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/utils@4.1.0
+  - @tko/bind@4.1.0
+  - @tko/provider.bindingstring@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/provider.virtual/package.json b/packages/provider.virtual/package.json
index 6f72026c1..8e1feef6a 100644
--- a/packages/provider.virtual/package.json
+++ b/packages/provider.virtual/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/provider.virtual",
   "description": "Binding provider for <!-- ko handler: ... --> virtual elements",
   "module": "dist/index.js",
@@ -9,9 +9,9 @@
   "author": "The Knockout Team",
   "license": "MIT",
   "dependencies": {
-    "@tko/provider.bindingstring": "^4.0.1",
-    "@tko/utils": "^4.0.1",
-    "@tko/bind": "^4.0.1"
+    "@tko/provider.bindingstring": "^4.1.0",
+    "@tko/utils": "^4.1.0",
+    "@tko/bind": "^4.1.0"
   },
   "homepage": "https://tko.io",
   "licenses": [
diff --git a/packages/provider/CHANGELOG.md b/packages/provider/CHANGELOG.md
index 342dc0060..f3c170071 100644
--- a/packages/provider/CHANGELOG.md
+++ b/packages/provider/CHANGELOG.md
@@ -1,5 +1,15 @@
 # @tko/provider
 
+## 4.1.0
+
+### Patch Changes
+
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/utils@4.1.0
+  - @tko/observable@4.1.0
+  - @tko/bind@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/provider/package.json b/packages/provider/package.json
index 6776afcb8..a02244c5a 100644
--- a/packages/provider/package.json
+++ b/packages/provider/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/provider",
   "description": "Abstract base class of tko Provider (HTML <-> Data Binding linker)",
   "module": "dist/index.js",
@@ -9,9 +9,9 @@
   "author": "The Knockout Team",
   "license": "MIT",
   "dependencies": {
-    "@tko/observable": "^4.0.1",
-    "@tko/utils": "^4.0.1",
-    "@tko/bind": "^4.0.1"
+    "@tko/observable": "^4.1.0",
+    "@tko/utils": "^4.1.0",
+    "@tko/bind": "^4.1.0"
   },
   "homepage": "https://tko.io",
   "licenses": [
diff --git a/packages/utils.component/CHANGELOG.md b/packages/utils.component/CHANGELOG.md
index d2a3ee29b..06a119cc2 100644
--- a/packages/utils.component/CHANGELOG.md
+++ b/packages/utils.component/CHANGELOG.md
@@ -1,5 +1,15 @@
 # @tko/utils.component
 
+## 4.1.0
+
+### Patch Changes
+
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/utils@4.1.0
+  - @tko/observable@4.1.0
+  - @tko/lifecycle@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/utils.component/package.json b/packages/utils.component/package.json
index 3479aba02..ede1e5b55 100644
--- a/packages/utils.component/package.json
+++ b/packages/utils.component/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/utils.component",
   "description": "Registry and loading utilities for web components",
   "module": "dist/index.js",
@@ -8,9 +8,9 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@tko/lifecycle": "^4.0.1",
-    "@tko/observable": "^4.0.1",
-    "@tko/utils": "^4.0.1"
+    "@tko/lifecycle": "^4.1.0",
+    "@tko/observable": "^4.1.0",
+    "@tko/utils": "^4.1.0"
   },
   "homepage": "https://tko.io",
   "licenses": [
diff --git a/packages/utils.functionrewrite/CHANGELOG.md b/packages/utils.functionrewrite/CHANGELOG.md
index 430d25de6..e8bb27e47 100644
--- a/packages/utils.functionrewrite/CHANGELOG.md
+++ b/packages/utils.functionrewrite/CHANGELOG.md
@@ -1,5 +1,7 @@
 # @tko/utils.functionrewrite
 
+## 4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/utils.functionrewrite/package.json b/packages/utils.functionrewrite/package.json
index 85ce01ff2..98c08cf92 100644
--- a/packages/utils.functionrewrite/package.json
+++ b/packages/utils.functionrewrite/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/utils.functionrewrite",
   "description": "Rewrite `function {}` as lambdas (=>)",
   "module": "dist/index.js",
diff --git a/packages/utils.jsx/CHANGELOG.md b/packages/utils.jsx/CHANGELOG.md
index cae574b5d..b3c02a9b4 100644
--- a/packages/utils.jsx/CHANGELOG.md
+++ b/packages/utils.jsx/CHANGELOG.md
@@ -1,5 +1,30 @@
 # @tko/utils.jsx
 
+## 4.1.0
+
+### Minor Changes
+
+- 7938c43: Add `options.jsxCleanBatchSize` (default `1000`) controlling JSX node cleanup
+  batching. Setting it to `0` runs cleanup synchronously on detach. Registered
+  via `defineOption` — the hardcoded `MAX_CLEAN_AT_ONCE` constant is gone, but
+  the new default matches it so production behavior is unchanged.
+
+  Fixes a `ReferenceError: Element is not defined` in the `cli-happy-dom` test
+  project where the 25ms batch timer could fire after happy-dom had torn down
+  DOM globals.
+
+### Patch Changes
+
+- Updated dependencies [bdac39c]
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/computed@4.1.0
+  - @tko/utils@4.1.0
+  - @tko/observable@4.1.0
+  - @tko/lifecycle@4.1.0
+  - @tko/bind@4.1.0
+  - @tko/provider.native@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/utils.jsx/package.json b/packages/utils.jsx/package.json
index 7a6b6568c..16cf3898d 100644
--- a/packages/utils.jsx/package.json
+++ b/packages/utils.jsx/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/utils.jsx",
   "description": "TKO JSX Rendering",
   "module": "dist/index.js",
@@ -20,12 +20,12 @@
   "author": "The Knockout Team",
   "license": "MIT",
   "dependencies": {
-    "@tko/bind": "^4.0.1",
-    "@tko/computed": "^4.0.1",
-    "@tko/lifecycle": "^4.0.1",
-    "@tko/observable": "^4.0.1",
-    "@tko/provider.native": "^4.0.1",
-    "@tko/utils": "^4.0.1"
+    "@tko/bind": "^4.1.0",
+    "@tko/computed": "^4.1.0",
+    "@tko/lifecycle": "^4.1.0",
+    "@tko/observable": "^4.1.0",
+    "@tko/provider.native": "^4.1.0",
+    "@tko/utils": "^4.1.0"
   },
   "homepage": "https://tko.io",
   "licenses": [
diff --git a/packages/utils.parser/CHANGELOG.md b/packages/utils.parser/CHANGELOG.md
index d8accf751..f694f3133 100644
--- a/packages/utils.parser/CHANGELOG.md
+++ b/packages/utils.parser/CHANGELOG.md
@@ -1,5 +1,47 @@
 # @tko/utils.parser
 
+## 4.1.0
+
+### Patch Changes
+
+- 49576cb: Drop dead polyfill probes from `@tko/utils`
+
+  Removes runtime feature detection for capabilities that all supported runtimes
+  (modern browsers, Node, Bun, happy-dom) already expose unconditionally. The
+  public API surface is preserved as one-line passthroughs in
+  `packages/utils/src/compat.ts` so existing consumers continue to work; these
+  shims are slated for removal in the next major.
+
+  - `functionSupportsLengthOverwrite` + `overwriteLengthPropertyIfSupported` —
+    `Object.defineProperty(fn, 'length', …)` has worked since IE9. Call sites
+    in `@tko/observable` now invoke `Object.defineProperty` directly. The
+    internal probe is gone; `overwriteLengthPropertyIfSupported` is preserved
+    on `@tko/utils` exports as an inline `Object.defineProperty` call.
+  - `useSymbols` + `createSymbolOrString` — `Symbol` is always defined; call
+    sites now use `Symbol(identifier)` directly. `createSymbolOrString` is
+    preserved as `s => Symbol(s)` on both `@tko/utils` exports and
+    `ko.utils.createSymbolOrString`.
+  - `stringTrim` + `stringStartsWith` — call sites use `String(value ?? '')
+.trim()` / `value.startsWith(prefix)` inline. Both names remain exported
+    from `@tko/utils` as inline passthroughs.
+  - `toggleDomNodeCssClass` SVGAnimatedString fallback — `classList` is
+    available on every supported `Element` (including SVG since SVG2).
+  - `parseJson` no longer routes through `stringTrim`; it trims inline when the
+    input is a string.
+
+  `packages/utils.parser/src/preparse.ts` also guards `str.match(bindingToken)`
+  against the `null` return case using `?? []` — previously relied on the match
+  never returning `null` for the transformed input.
+
+  Patch-level for all packages: zero observable surface change for consumers
+  not reaching into internal probes (`useSymbols`, `functionSupportsLengthOverwrite`),
+  which had no monorepo callers.
+
+- Updated dependencies [3aea21c]
+- Updated dependencies [49576cb]
+  - @tko/utils@4.1.0
+  - @tko/observable@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/utils.parser/package.json b/packages/utils.parser/package.json
index 9f9f73cb1..8e25f0275 100644
--- a/packages/utils.parser/package.json
+++ b/packages/utils.parser/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/utils.parser",
   "description": "Parse the Javascript-like language used in data-bind and other HTML attributes (CSP-safe)",
   "module": "dist/index.js",
@@ -8,8 +8,8 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@tko/observable": "^4.0.1",
-    "@tko/utils": "^4.0.1"
+    "@tko/observable": "^4.1.0",
+    "@tko/utils": "^4.1.0"
   },
   "homepage": "https://tko.io",
   "licenses": [
diff --git a/packages/utils/CHANGELOG.md b/packages/utils/CHANGELOG.md
index fc95d7093..8f5900fab 100644
--- a/packages/utils/CHANGELOG.md
+++ b/packages/utils/CHANGELOG.md
@@ -1,5 +1,64 @@
 # @tko/utils
 
+## 4.1.0
+
+### Patch Changes
+
+- 3aea21c: Modernize synthetic event construction
+
+  `triggerEvent` (exported from `@tko/utils`) now builds synthetic events using
+  `new MouseEvent`/`KeyboardEvent`/`Event` constructors instead of the
+  deprecated `document.createEvent('HTMLEvents')` + `initEvent(...)` path. This
+  restores native side-effects in modern DOM implementations (e.g. synthetic
+  clicks toggle checkbox `.checked` in happy-dom) without changing behavior in
+  real browsers. `relatedTarget` is still set to the target element for mouse
+  events to match the previous init-event argument list.
+
+  `@tko/binding.core` event handler no longer assigns the legacy
+  `event.cancelBubble = true` before calling `event.stopPropagation()` — the
+  assignment is redundant on modern events and readonly on some implementations.
+
+  `@tko/provider.component` now uses `Object.prototype.toString.call(node)` to
+  detect `HTMLUnknownElement` rather than `'' + node`, which is immune to
+  user-land `toString` overrides on custom elements.
+
+- 49576cb: Drop dead polyfill probes from `@tko/utils`
+
+  Removes runtime feature detection for capabilities that all supported runtimes
+  (modern browsers, Node, Bun, happy-dom) already expose unconditionally. The
+  public API surface is preserved as one-line passthroughs in
+  `packages/utils/src/compat.ts` so existing consumers continue to work; these
+  shims are slated for removal in the next major.
+
+  - `functionSupportsLengthOverwrite` + `overwriteLengthPropertyIfSupported` —
+    `Object.defineProperty(fn, 'length', …)` has worked since IE9. Call sites
+    in `@tko/observable` now invoke `Object.defineProperty` directly. The
+    internal probe is gone; `overwriteLengthPropertyIfSupported` is preserved
+    on `@tko/utils` exports as an inline `Object.defineProperty` call.
+  - `useSymbols` + `createSymbolOrString` — `Symbol` is always defined; call
+    sites now use `Symbol(identifier)` directly. `createSymbolOrString` is
+    preserved as `s => Symbol(s)` on both `@tko/utils` exports and
+    `ko.utils.createSymbolOrString`.
+  - `stringTrim` + `stringStartsWith` — call sites use `String(value ?? '')
+.trim()` / `value.startsWith(prefix)` inline. Both names remain exported
+    from `@tko/utils` as inline passthroughs.
+  - `toggleDomNodeCssClass` SVGAnimatedString fallback — `classList` is
+    available on every supported `Element` (including SVG since SVG2).
+  - `parseJson` no longer routes through `stringTrim`; it trims inline when the
+    input is a string.
+
+  `packages/utils.parser/src/preparse.ts` also guards `str.match(bindingToken)`
+  against the `null` return case using `?? []` — previously relied on the match
+  never returning `null` for the transformed input.
+
+  Patch-level for all packages: zero observable surface change for consumers
+  not reaching into internal probes (`useSymbols`, `functionSupportsLengthOverwrite`),
+  which had no monorepo callers.
+
+- Updated dependencies [49576cb]
+  - @tko/builder@4.1.0
+  - @tko/provider@4.1.0
+
 ## 4.0.1
 
 ### Patch Changes
diff --git a/packages/utils/package.json b/packages/utils/package.json
index 68377f6c2..b026750d9 100644
--- a/packages/utils/package.json
+++ b/packages/utils/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "4.0.1",
+  "version": "4.1.0",
   "name": "@tko/utils",
   "description": "TKO Utilities",
   "type": "module",
@@ -24,8 +24,8 @@
   },
   "homepage": "https://tko.io",
   "dependencies": {
-    "@tko/provider": "^4.0.1",
-    "@tko/builder": "^4.0.1"
+    "@tko/provider": "^4.1.0",
+    "@tko/builder": "^4.1.0"
   },
   "licenses": [
     {