* 5.2.1 (2020-12-18)

* bug #39555 [FrameworkBundle] Fix NFS detection on macOs (jderusse)

* bug #39545 [Notifier] [Mattermost] Host is required (OskarStark)

* bug #39548 [Notifier] [Infobip][Zulip] Host is required (OskarStark)

* bug #39550 [HttpFoundation] keep turning dots to underscores when using Request::create() (nicolas-grekas)

* bug #39538 [Notifier] Fix parsing Dsn with empty user/password (OskarStark)

* bug #39531 [Mailer] Fix parsing Dsn with empty user/password (OskarStark)

* bug #39492 [Notifier] [Discord] Use private const and mb_strlen() (OskarStark)

* bug #39522 [Notifier] Set message id on SentMessage (OskarStark)

* bug #39532 [Notifier] Fix toString when optional parameter is not set (OskarStark)

* bug #39518 [Ldap] Incorrect determination of RelativeDistinguishedName for the "move" operation (astepin)

* bug #39525 [VarDumper] dont hide any nodes until JS is proven to work (nicolas-grekas)

* bug #39498 [DoctrineBridge] Guess correct form types for DATE_IMMUTABLE and DATETIME_IMMUTABLE (guillaume-sainthillier)

* bug #39510 [Notifier]  [Free Mobile] Could not use custom host in DSN (OskarStark)

* bug #39515 [Notifier] Fix wrong package name (OskarStark)

* bug #39514 [Notifier] Fix wrong package names (OskarStark)

* bug #39502 Add missing symfony/deprecation-contracts requirement - 5.2 (jderusse)

* bug #39494 Add missing symfony/deprecation-contracts requirement (jderusse)

* bug #39360 [FrameworkBundler] Fix cache:clear with buildDir (jderusse)

* bug #39476 [Lock] Prevent store exception break combined store (dzubchik)

* bug #39478 [FrameworkBundle] Fix missing kernel.build_dir on cache clear (chalasr)

* bug #39456 [Notifier] [Free Mobile] Fix wrong scheme in mapping (OskarStark)

* bug #39442 Fix enabled key for ratelimiter config (pierredup)

* bug #39299 [PropertyInfo][Serializer] Fixed extracting ignored properties for Serializer (javer)

* bug #39433 [Cache] fix setting "read_timeout" when using Redis (nicolas-grekas)

* bug #39228 [HttpClient] Fix content swallowed by AsyncClient initializer (jderusse)

* bug #39420 [Cache] Prevent notice on case matching metadata trick (bastnic)

* bug #39413 [Notifier] [Discord] Make webhookId argument required (OskarStark)

* bug #39203 [DI] Fix not working if only "default_index_method" used (malteschlueter)

* bug #39409 [Notifier] [Twilio] Add tests (OskarStark)

* bug #39401 [DoctrineBridge] no-op RegisterUidTypePass if DBAL types aren't loaded (craue)

* bug #39417 [Form] Fix UUID exception (jderusse)

* bug #39142 [Config] Stop treating multiline resources as globs (michaelKaefer)

* bug #39341 [Form] Fixed StringUtil::trim() to trim ZERO WIDTH SPACE (U+200B) and SOFT HYPHEN (U+00AD) (pmishev)

* bug #39268 [HttpClient] Use decoration instead of class replacement for mock factory (GaryPEGEOT)

* bug #39334 [Config][TwigBundle] Fixed syntax error in config (Nyholm)

* bug #39196 [DI] Fix Xdebug 3.0 detection (vertexvaar)

* bug #39375 [SecurityBundle] fix LDAP-based HTTP Basic Auth entry point registration (xabbuh)

* bug #39226 [PhpUnitBridge] Fix disabling DeprecationErrorHandler from PHPUnit configuration file (fancyweb)

* bug #39298 [Cache] Fixed incorrect usage of UNLINK with PHPRedis with Redis < 4.0 (wickex)

* bug #39361 [FrameworkBundle] acces public-deprecated services via the private container to remove false-positive deprecations (nicolas-grekas)

* bug #39358 [HttpFoundation] fix parsing some special chars with HeaderUtils::parseQuery() (nicolas-grekas)

* bug #39357 [FrameworkBundle] fix preserving some special chars in the query string (nicolas-grekas)

* bug #39310 [Notifier] Add exception for deprecated slack dsn (malteschlueter)

* bug #39271 [HttpFoundation] Fix TypeError: Argument 1 passed to JsonResponse::setJson() must be of the type string, object given (sidz)

* bug #39251 [DependencyInjection] Fix container linter for union types (derrabus)

* bug #39336 [Config] YamlReferenceDumper: No default value required for VariableNode with array example (Nyholm)

* bug #39333 [Form] do not apply the Valid constraint on scalar form data (lchrusciel, xabbuh)

* bug #39331 [PhpUnitBridge] Fixed PHPunit 9.5 compatibility (wouterj)

* bug #39220 [HttpKernel] Fix bug with whitespace in Kernel::stripComments() (ausi)

* bug #39252 [Mime] Leverage PHP 8's detection of CSV files (derrabus)

* bug #39313 [FrameworkBundle] TextDescriptor::formatControllerLink checked method… (fjogeleit)

* bug #39286 [HttpClient] throw clearer error when no scheme is provided (BackEndTea)

* bug #39267 [Yaml] fix lexing backslashes in single quoted strings (xabbuh)

* bug #39151 [DependencyInjection] Fixed incorrect report for private services if required service does not exist (Islam93)

* bug #39236 [Notifier] Fix slack section block (norkunas)

* bug #39274 [Yaml] fix lexing mapping values with trailing whitespaces (xabbuh)

* bug #39256 [Workflow] Fixed case when the marking store is not defined (lyrixx)

* bug #39244 [String] Fix Notice when argument is empty string (moldman)

* bug #39270 [Inflector] Fix Notice when argument is empty string (moldman)

* bug #39263 [Security] more defensive PasswordMigratingListener (romaricdrigon)

* bug #39261 [Security] fix #39249, default entry_point compiler pass was returning too early (romaricdrigon)

* bug #39247 [Security] remove return type definition in order to avoid type juggling (adeptofvoltron)

* bug #39223 [Console] Re-enable hyperlinks in Konsole/Yakuake (OndraM)

* bug #39241 [Yaml] fix lexing inline sequences/mappings with trailing whitespaces (Nyholm, xabbuh)

* bug #39243 [Filesystem] File existence check before calling unlink method (gechetspr)