Here is a list of what was fixed since 11.5.0:

• 2021-10-12 dcba2a7ce9 [RELEASE] Release of TYPO3 11.5.1 (thanks to Benni Mack)
• 2021-10-12 b3790781e1 [BUGFIX] Restore same height for Tree and Docheader (thanks to Oliver Bartsch)
• 2021-10-12 80fa617487 [TASK] Improve PHPDoc of ResourceStorage::sanitizeFileName (thanks to Stephan Großberndt)
• 2021-10-12 694bdc5132 [BUGFIX] Add fallback for undefined key warning in PHP8 (thanks to Jochen Roth)
• 2021-10-12 8585fa77e9 [TASK] Show name of table when editing record (thanks to Georg Ringer)
• 2021-10-12 d21dcb2b17 [TASK] Use str_contains instead of strpos where possible (thanks to Nikita Hovratov)
• 2021-10-12 679ca065db [TASK] Update documentation links (thanks to Susanne Moog)
• 2021-10-12 dc4c9c1bdf [BUGFIX] Fix workspace state handling (thanks to Oliver Bartsch)
• 2021-10-12 bcc2d11e9d [BUGFIX] Render HTML tags in CSH (thanks to Oliver Hader)
• 2021-10-12 2a5c83e16d [TASK] Update composer dev dependencies (thanks to Wouter Wolters)
• 2021-10-11 d7d5a5fcad [BUGFIX] Ensure string is passed to f:sanitize.html view helper (thanks to Oliver Hader)
• 2021-10-11 4582c9343f [BUGFIX] Incomplete setup in PhpErrorCodeViewHelperTest (thanks to Christian Kuhn)
• 2021-10-11 61d760e792 [BUGFIX] Undefined array keys related to workspaces (thanks to Francois Suter)
• 2021-10-11 6eed2f6b97 [BUGFIX] Avoid ReferenceIndex->enableRuntimeCache() in EXT:impexp (thanks to Christian Kuhn)
• 2021-10-11 47274ba94e [TASK] Upgrade @types/bootstrap to 5.1.6 (thanks to Nikita Hovratov)
• 2021-10-11 0a0e726575 [BUGFIX] PHP 8.0 warnings in QueryGenerator (thanks to Christian Kuhn)
• 2021-10-11 e256d2e6c1 [BUGFIX] Return empty stages list in LIVE workspace (thanks to Francois Suter)
• 2021-10-11 982308b542 [BUGFIX] Show broken links for all languages (thanks to Sybille Peters)
• 2021-10-11 c86b292962 [BUGFIX] Allow FilePathSanitizer to return absolute paths (thanks to Helmut Hummel)
• 2021-10-11 1789002203 [BUGFIX] No exclude for transOrigPointerField (thanks to Christian Kuhn)
• 2021-10-11 a39765e066 [BUGFIX] Prevent undefined array key access in modAccess() (thanks to Oliver Bartsch)
• 2021-10-11 eef89fac9f [BUGFIX] Fix undefined array key errors for PHP 8.0 (thanks to Stephan Sellner)
• 2021-10-11 b8942cf2b7 [BUGFIX] Fix PHP8 warning from PageSlugCandidateProvider (thanks to Stefan Bürk)
• 2021-10-11 245c13b629 [BUGFIX] Initialize backenduser for RedirectServiceTest (thanks to Stefan Bürk)
• 2021-10-11 c4624caebd [BUGFIX] Initialize language object in SlugServiceTest (thanks to Stefan Bürk)
• 2021-10-11 b6cbade932 [BUGFIX] PHP8.0 warning from ext:recycler tests (thanks to Stefan Bürk)
• 2021-10-11 a5bbdc272b [BUGFIX] (Re)initalize beuser based LanguageService after beuser (thanks to Stefan Bürk)
• 2021-10-11 b7ea895c3d [BUGFIX] Check for complete database configuration before connecting (thanks to Stefan Bürk)
• 2021-10-11 b7d33abda6 [BUGFIX] Move virtual storage 0 back to public path (thanks to Helmut Hummel)
• 2021-10-11 f489cb503b [TASK] Add class name to deprecated cObj for plugins message (thanks to Stefan Bürk)
• 2021-10-11 eb4b65b1f3 [TASK] Set visibility of Clipboard->getLocalizations to protected (thanks to Nikita Hovratov)
• 2021-10-11 bd637d374b [BUGFIX] Fix some minor Composer mode path inconsistencies (thanks to Helmut Hummel)
• 2021-10-10 463597c189 [BUGFIX] access-restricted subpages of sysfolders return 403 (thanks to Benni Mack)
• 2021-10-10 f6c25aae6d [BUGFIX] PHP8.0 warning in CleanerTask (thanks to Stefan Bürk)
• 2021-10-10 08cd87c0ba [BUGFIX] Fix undefined index and offset warning in lowlevel QueryGenerator (thanks to Stefan Bürk)
• 2021-10-09 c746c18601 [BUGFIX] Properly set softRefParams in LinkAnalyzer (thanks to Oliver Bartsch)
• 2021-10-09 3f8443579a [BUGFIX] Add correct value for $itemsCriteriaField (thanks to Jochen Roth)
• 2021-10-09 34a9ff66b0 [BUGFIX] Align default value of displayThumbs (thanks to Oliver Bartsch)
• 2021-10-09 7fa71a1d22 [BUGFIX] Add parenthesis where operation result is enforced (thanks to Nikita Hovratov)
• 2021-10-08 2f96ed6a79 [BUGFIX] Set remote identifier for checking extension dependencies (thanks to Benni Mack)
• 2021-10-08 09c651a08d [BUGFIX] Prevent undefined key warnings in ProductionExceptionHandler (thanks to Robert Kärner)
• 2021-10-08 bd25eb806f [BUGFIX] Add autocomplete attribute to confirmation password (thanks to Oliver Bartsch)
• 2021-10-08 8d3e14ed5a [TASK] Ensure record_commit parameters are not reused (thanks to Marcel Schüßler)
• 2021-10-08 a3ec0dfd5d [BUGFIX] Do not prefix source set path with absRefPrefix (thanks to Jochen Roth)
• 2021-10-08 0f0b4b9f2c [TASK] Apply ParamTypeDeclarationRector on private methods (thanks to Alexander Schnitzler)
• 2021-10-08 27360c3875 [BUGFIX] Fix undefined array key warnings (thanks to Oliver Bartsch)
• 2021-10-08 3d3372c85c [BUGFIX] Prevent PHP 8 warnings during content rendering (thanks to Alexander Stehlik)
• 2021-10-08 a1cd9b5624 [BUGFIX] Prevent undefined key warnings in suggest wizard (thanks to Robert Kärner)
• 2021-10-08 46e8a7025a [BUGFIX] Clean up clipboard before using it in ContextMenu (thanks to Oliver Bartsch)
• 2021-10-08 ec7fc82fb3 [BUGFIX] Properly store and retrieve task group collapse state (thanks to Oliver Bartsch)
• 2021-10-08 0b9d925f62 [BUGFIX] Catch UnknownLinkHandlerException in view helper (thanks to Oliver Bartsch)
• 2021-10-08 e2c06db7e0 [BUGFIX] Fix non-matching values in functional test datasets (thanks to Nikita Hovratov)
• 2021-10-08 f35e7100c5 [TASK] Unify autoSizeMax logic (thanks to Nikita Hovratov)
• 2021-10-08 cc0c6b277b [BUGFIX] Restore inconsistent language highlighting (thanks to Oliver Bartsch)
• 2021-10-08 4f7416a823 [BUGFIX] Properly handle array key access in ExtendedTemplateService (thanks to Oliver Bartsch)
• 2021-10-08 c952515534 [BUGFIX] PHP 8.0 warning from ContentObjectRenderer (thanks to Christian Kuhn)
• 2021-10-08 ba51304887 [BUGFIX] Fix EXT:felogin FlexForm (thanks to Oliver Bartsch)
• 2021-10-07 dd0c8301b1 [BUGFIX] Set fe_user email field to eval "email" (thanks to Jochen Roth)
• 2021-10-07 768bd1cd43 [BUGFIX] Extbase UriBuilder warning in Backend context (thanks to Christian Kuhn)
• 2021-10-07 2bd19657e7 [BUGFIX] Add fallback for link details (thanks to Jochen Roth)
• 2021-10-07 ad2a858bc4 [TASK] Improve links in footer of error page (thanks to Georg Ringer)
• 2021-10-07 77056aedd8 [BUGFIX] Incomplete setup in ImageViewHelperTest (thanks to Christian Kuhn)
• 2021-10-07 8a210a68c5 [BUGFIX] Use proper call to stdWrapValue (thanks to Georg Ringer)
• 2021-10-07 9aa0acd819 [BUGFIX] Incomplete setup in FileViewHelperTest (thanks to Christian Kuhn)
• 2021-10-07 933d5a0281 [BUGFIX] Incomplete setup in ScriptViewHelperTest (thanks to Christian Kuhn)
• 2021-10-07 602f2f756a [BUGFIX] Correct VH name in HtmlentitiesDecodeViewHelperTest (thanks to Christian Kuhn)
• 2021-10-07 2a2f6288eb [TASK] Rename method inside PageLayoutController (thanks to Benni Mack)
• 2021-10-07 9f228e9959 [BUGFIX] Return ResponseInterface in ext:fluid_test action (thanks to Christian Kuhn)
• 2021-10-07 84bc062e72 [BUGFIX] errorHandling setup in site based functional tests (thanks to Christian Kuhn)
• 2021-10-07 c1d2ad4f69 [BUGFIX] Container registration of ext:fluid_test VH's (thanks to Christian Kuhn)
• 2021-10-07 c69be088eb [BUGFIX] Rebuild redirect cache after changing slug (thanks to Georg Ringer)
• 2021-10-07 4d00b22804 [BUGFIX] Use proper bootstrap styles for "Make Query" in DB check (thanks to Marcin Sągol)
• 2021-10-07 1506c257b0 [BUGFIX] Fix undefined array key errors (thanks to Nikita Hovratov)
• 2021-10-07 5e8886d9fe [BUGFIX] Avoid $GLOBALS['TYPO3_REQUEST'] warning in Clipboard (thanks to Christian Kuhn)
• 2021-10-07 f778cfe355 [BUGFIX] Fix TypoScript object browser search (thanks to Oliver Bartsch)
• 2021-10-07 3a9bac11e8 [TASK] Quote identifier in messages with " instead of ' for ext:impexp (thanks to Stefan Bürk)
• 2021-10-07 363b6b4fcc [TASK] Add missing breaking.rst about service injection in validators (thanks to Torben Hansen)
• 2021-10-07 08c1d86332 [TASK] Raise doctrine/dbal:^2.13.4 (thanks to Stefan Bürk)
• 2021-10-07 84d648a7cd [BUGFIX] Correctly close anchor tag in object browser (thanks to Oliver Bartsch)
• 2021-10-07 16804cc5dd [BUGFIX] Fix invalid json responses for empty page trees (thanks to Benjamin Franzke)
• 2021-10-06 65580403cf [TASK] Adjust test expectations for php8.1 changed defaults (thanks to Stefan Bürk)
• 2021-10-06 ec4c0517ff [TASK] Load ext:beuser in beuser functional test (thanks to Christian Kuhn)
• 2021-10-06 053a365bac [TASK] Skip one unit test dataset only for php81 until php bug is fixed (thanks to Stefan Bürk)
• 2021-10-06 ced432411e [BUGFIX] Fallback optional settings in SiteBasedTestTrait (thanks to Christian Kuhn)
• 2021-10-06 85e2f269b7 [BUGFIX] Incomplete setUp() in ClipboardTest (thanks to Christian Kuhn)
• 2021-10-06 d45d1d967d [BUGFIX] Incomplete setup in TcaCategoryTest (thanks to Christian Kuhn)
• 2021-10-06 99ddda5100 [BUGFIX] Replace duplicated id in Scheduler edit task template (thanks to Simon Schaufelberger)
• 2021-10-06 7eab78a1e5 [TASK] Raise typo3/testing-framework:^6.11.3 (thanks to Christian Kuhn)
• 2021-10-06 f5b582bab9 [BUGFIX] Adjust chosen to use flex-form in bootstrap context (thanks to Oliver Bartsch)
• 2021-10-06 b40dbdb491 [BUGFIX] Address undefined array index warnings in PHP8 (thanks to Oliver Hader)
• 2021-10-06 cc98e45815 [BUGFIX] Properly cast possible database values (thanks to Oliver Bartsch)
• 2021-10-06 9852c63a04 [BUGFIX] Add absRefPrefix on cached pages with uncached content (thanks to Robert Kärner)
• 2021-10-06 ab5c62d68e [BUGFIX] Show edit options only if editor got access (thanks to Georg Ringer)
• 2021-10-06 9fccd106cd [BUGFIX] Use correct module name for checking permissions to help module (thanks to Georg Ringer)
• 2021-10-05 d0c9d75739 [BUGFIX] Move SoftReferenceParserFactory DI config to correct sysext (thanks to Nikita Hovratov)
• 2021-10-05 619e94eb4f [BUGFIX] Resolve site configuration in FlexForm (thanks to Andreas Fernandez)
• 2021-10-05 bb6d3f7b3a [BUGFIX] Populate composer name to extension key map early (thanks to Helmut Hummel)
• 2021-10-05 c33bbffe5e [TASK] Set TYPO3 version to 11.5.1-dev (thanks to Oliver Hader)