Released on Sunday, October 25 2026

What's Changed

• Removed temporary copies when serializing text that needs no HTML escaping @perfloop-agent in #1388
• Fixed INode.Equals (isEqualNode) to compare what the DOM spec compares: character data, doctype identifiers, processing instructions, element prefixes and attribute local names, no longer base URLs, without overflowing the stack on deep trees
• Fixed IAttr.Equals comparing the prefix instead of the local name
• Fixed IDocument.Import (importNode) returning nodes owned by the source document instead of the importing one
• Fixed IDocument.Import accepting a shadow root instead of throwing NotSupported
• Fixed INode.Clone and Import overflowing the stack on deeply nested trees and templates
• Fixed a shallow clone of a <template> copying its contents
• Fixed serializing < and > in attribute values unescaped, which let markup break out when reparsed under different rules (mutation XSS); they are now written as < and > like browsers do since the HTML spec change of May 2025
• Fixed IRange.CopyContent and ExtractContent overflowing the stack on deeply nested ranges
• Fixed Dispatch (dispatchEvent) returning true for a canceled event
• Fixed MutationObserver not observing a document itself and throwing for one without a root element
• Fixed MutationObserver.Disconnect keeping the previous targets for a later Connect
• Fixed a failing navigation or submission from DoClick crashing the process; it is reported as a context error
• Fixed URLSearchParams treating non-ASCII values as single bytes and leaving + undecoded @NotAFlightRisk in #1390
• Added the IHtmlSelectElement.SelectedIndex setter
• Added HtmlParserOptions.MaximumDepth (default 512) to stop deeply nested markup from building trees that overflow the stack
• Added focusing of elements with a tabindex and blurring of any focused element
• Added DoClickAsync to await a click's navigation or form submission
• Added toggling the parent <details> when clicking its <summary>
• Added declarative shadow DOM: the parser attaches <template shadowrootmode="open"> (or closed) as the shadow root of its parent
• Added :host(<compound>), and selectors in a shadow tree reaching its host (only through :host)
• Released 1.8.6 by @FlorianRappl in #1391

New Contributors

• @perfloop-agent made their first contribution in #1388

Full Changelog: v1.8.5...v1.8.6

Released on Thursday, October 15 2026

What's Changed

• Fixed select selectedness and option dirtiness across mutations, reset and cloning (#1384) @PrzemyslawKlys
• Fixed fragment parsing losing the context document's quirks and limited-quirks modes (#1382) @PrzemyslawKlys
• Fixed :lang() inheritance and namespace precedence in HTML and foreign content (#1379) @PrzemyslawKlys
• Fixed URLSearchParams cutting values at a second = such as token=abc== (#1385) @NotAFlightRisk
• Released 1.8.5 by @FlorianRappl in #1386

Full Changelog: v1.8.4...v1.8.5

Released on Wednesday, October 7 2026

What's Changed

• Improved selection when parsing <select> (#1364) @PrzemyslawKlys
• Updated constraint validation eligibility of fieldset and output elements (breaking behavior change) (#1373) @PrzemyslawKlys
• Fixed change of <select> value (IsSelected) (#1365) @PrzemyslawKlys
• Fixed indeterminate input state when cloning (#1367) @PrzemyslawKlys
• Fixed <select> form submission including unselected options and options in disabled groups (#1366) @PrzemyslawKlys
• Fixed option indexes inside option groups (#1368) @PrzemyslawKlys
• Fixed selecting an option leaving other single-select options selected (#1372) @PrzemyslawKlys
• Fixed validity checks for controls excluded from validation (#1370) @PrzemyslawKlys
• Fixed template content document when adopting a subtree (#1374) @PrzemyslawKlys
• Fixed checking a radio leaving other group members checked (#1371) @PrzemyslawKlys
• Fixed parsed radio checkedness depending on attribute order @PrzemyslawKlys
• Fixed SVG annotation-xml elements being treated as HTML integration points @NotAFlightRisk
• Fixed required radio validation across group members (#1369) @PrzemyslawKlys
• Released 1.8.4 by @FlorianRappl in #1377

New Contributors

• @NotAFlightRisk made their first contribution in #1376

Full Changelog: v1.8.3...v1.8.4

Released on Wednesday, September 30 2026

What's Changed

• Improved cancellation of queued timer callbacks (#1357) @PrzemyslawKlys
• Improved configuration / setup performance (#1360) @PrzemyslawKlys
• Fixed form submission ignoring sandbox restrictions (#1358) @PrzemyslawKlys
• Fixed <base> elements not following frozen document base URL and tree-order mutation rules (#1355, #1362)
• Fixed native Unloading handlers subscribing to unloading instead of beforeunload (#1354) @PrzemyslawKlys
• Added OnReset event to inform script hosts of native listener removals (#1356) @PrzemyslawKlys
• Added pull-based HTML serialization stream (#1361) @PrzemyslawKlys
• Released 1.8.3 by @FlorianRappl in #1363

New Contributors

• @PrzemyslawKlys made their first contribution in #1356

Full Changelog: v1.8.2...v1.8.3

Released on Friday, September 18 2026

What's Changed

• Improved attribute selector serialization to write only the case-sensitivity modifier that was specified (#1351)
• Improved id/name lookup on collections (document.forms["x"], form.elements["x"], ...) to enumerate the underlying sequence once instead of twice
• Improved performance of form.elements / fieldset.elements by walking the tree directly (#1350)
• Improved GetElementsByTagName / GetElementsByClassName traversal to stop double-scanning each element's children
• Improved selector specificity (Selectors.Specificity, ComplexSelector.Specificity) to be computed once instead of recomputed on every read
• Improved ListSelector.GetMatchingSelector to sort its selectors once instead of on every call
• Improved performance of HTML tree construction by keeping mutation logic out of it (#1347)
• Improved performance of DOM mutations by building a mutation record only when an observer will consume it (#1347)
• Improved performance of parser attribute duplication check
• Fixed Document.Forms allocating a new collection instance per read, contradicting its own [DomSameObject] contract
• Fixed classList and the other reflected token lists writing their content attribute without running the attribute change steps or queueing a mutation record
• Fixed clearing a reflected boolean attribute such as disabled removing it without running the attribute change steps or queueing a mutation record
• Fixed vulnerability via SVG style serialization (GHSA-cgp3-27rh-pcp2)
• Fixed a StackOverflowException when parsing a document with deeply nested unclosed <template> elements
• Added Document.MutationVersion, a synchronous counter of DOM mutations that a parse leaves unchanged (#1344, #1347)
• Released 1.8.2 by @FlorianRappl in #1353

New Contributors

• @RichardJansma made their first contribution in #1352

Full Changelog: v1.8.1...v1.8.2

Released on Thursday, September 10 2026

What's Changed

• Updated DoFocus and DoBlur to apply to form elements
• Improved explicit form ownership to take precedence over ancestor forms for connected controls (#1323) @sebastienros
• Fixed HTML hyperlink pseudo-classes omitting empty href and matching link elements (#1337) @sebastienros
• Fixed HTML-namespace element creation losing local-name case (#1327) @sebastienros
• Fixed :enabled incorrectly matching HTML links with nonempty href (#1324) @sebastienros
• Fixed changing focus of elements
• Released 1.8.1 by @FlorianRappl in #1343

New Contributors

• @sebastienros made their first contribution in #1338

Full Changelog: v1.8.0...v1.8.1

Released on Saturday, September 5 2026

What's Changed

• Improved AngleSharp's test website
• Fixed script data escaped state potentially not bouncing back correctly
• Added the DomSameObject annotation for the respective IDL members (#1314) @lahma
• Added the DomReturnType annotation for methods returning a different IDL type (#1318)
• Released 1.8.0 by @FlorianRappl in #1317

Full Changelog: v1.7.3...v1.8.0

Released on Thursday, September 3 2026

What's Changed

• Improved tracking of parse exceptions in the HtmlParser (#1315) @lahma
• Fixed tokenizer buffer overrun on encoding change (#1290) @jafin
• Fixed selector text dropping the nth-child of clause (#1292) @jafin
• Fixed selector text dropping the case-insensitive (#1291) @jafin
• Fixed selector specificity carrying between fields instead of saturating (#1300) @meziantou
• Fixed condition check for disposed state in ReturnToPool (#1296) @meziantou
• Fixed ArgumentOutOfRangeException CSS escapes (#1299) @meziantou
• Fixed whitespace around An+B CSS selector notations (#1297)
• Fixed unsupported pseudo-classes matching everything (#1295)
• Fixed DomException for invalid foreign attribute names such as xml:lang[ (#1294)
• Fixed script data escaped state leaving escaped mode too early (#1298)
• Fixed CurrentScript not indicating the currently executing script (#1308) @lahma
• Fixed returned missing attribute-properties to use empty string instead of null (#1313) @lahma
• Fixed removal of data-* attributes (#1310) @lahma
• Added missing DomName/DomAccessor annotations (#1301) @meziantou
• Added missing DomLiterals attribute to AdjacentPosition (#1311) @lahma
• Released 1.7.3 by @FlorianRappl in #1302

Full Changelog: v1.7.2...v1.7.3

Released on Sunday, August 23 2026

What's Changed

• Fixed matching of annotation-xml encoding to be case-insensitive (#1284) @arpitjain099
• Fixed <xmp> usage in <select> elements
• Added ability to parse immutable byte buffers without a stream (#1286) @dv00d00
• Released 1.7.2 by @FlorianRappl in #1288

New Contributors

• @arpitjain099 made their first contribution in #1284

Full Changelog: 1.7.1...v1.7.2

Released on Wednesday, August 5 2026

• Migrated the build system from NUKE to Fallout by @jafin in #1275
• Improved WHATWG Url specification (#802) @jafin
• Improved tokenizer read performance (#1274) @dv00d00
• Fixed auxiliary browsing context lifetime (#1278) @jafin
• Fixed duplicated DomName attributes on DOM geometry
• Fixed document.open() destroying the DOM tree in case of encoding problems (#1276)
• Fixed source references having wrong line (#1280)
• Released 1.7.1 by @FlorianRappl in #1281

Full Changelog: 1.7.0...v1.7.1