v12.1.1

## v12.1.1 (2026-09-28)

#### Bug fixes
* `common`, `core`, `microservices`, `testing`
  * [#17893](https://github.com/nestjs/nest/pull/17893) fix(common): logger bugs in json output, level changes, fatal and buffered logs ([@kamilmysliwiec](https://github.com/kamilmysliwiec))
* `microservices`
  * [#17891](https://github.com/nestjs/nest/pull/17891) fix(microservices): let the mqtt client retry after a failed connect ([@hktitof](https://github.com/hktitof))
  * [#17888](https://github.com/nestjs/nest/pull/17888) fix(microservices): keep tcp event listeners across reconnects ([@KAPUIST](https://github.com/KAPUIST))
  * [#17887](https://github.com/nestjs/nest/pull/17887) fix(microservices): ignore events from a replaced tcp client socket ([@KAPUIST](https://github.com/KAPUIST))
  * [#17878](https://github.com/nestjs/nest/pull/17878) fix(microservices): keep a newer nats connection when a stale one fails ([@hktitof](https://github.com/hktitof))
  * [#17869](https://github.com/nestjs/nest/pull/17869) fix(microservices): keep a newer kafka connection when a stale one fails ([@kamilmysliwiec](https://github.com/kamilmysliwiec))
  * [#17865](https://github.com/nestjs/nest/pull/17865) fix(microservices): let the rmq client retry after a failed connect ([@hktitof](https://github.com/hktitof))
  * [#17866](https://github.com/nestjs/nest/pull/17866) fix(microservices): reply on the request channel when redis wildcards are enabled ([@fadiroot](https://github.com/fadiroot))
  * [#17861](https://github.com/nestjs/nest/pull/17861) fix(microservices): recover the nats client after it gives up reconnecting ([@xia-chao](https://github.com/xia-chao))
* `common`
  * [#17884](https://github.com/nestjs/nest/pull/17884) fix(common): preserve string enum values matching numeric member names ([@KAPUIST](https://github.com/KAPUIST))
* `core`
  * [#17871](https://github.com/nestjs/nest/pull/17871) fix(core): detect circular dependencies across more than two providers ([@erezcor](https://github.com/erezcor))
* `platform-fastify`
  * [#17867](https://github.com/nestjs/nest/pull/17867) fix(fastify): treat a JSON content type with parameters as JSON in reply() ([@fadiroot](https://github.com/fadiroot))
* `core`, `testing`
  * [#17860](https://github.com/nestjs/nest/pull/17860) fix(core): honor class and factory overrides of value providers ([@lehafari](https://github.com/lehafari))

#### Enhancements
* `common`
  * [#17876](https://github.com/nestjs/nest/pull/17876) fix(common): reject non-numeric items in ParseArrayPipe with items Number ([@SulimanAbdulrazzaq](https://github.com/SulimanAbdulrazzaq))
* `microservices`
  * [#17863](https://github.com/nestjs/nest/pull/17863) feat(microservices): export deserializers from the package root ([@lazerg](https://github.com/lazerg))

#### Committers: 13
- Abdellatif Anaflous ([@hktitof](https://github.com/hktitof))
- Alejandro ([@lehafari](https://github.com/lehafari))
- Daniel Pinto ([@Cayan](https://github.com/Cayan))
- Dharmik Sondagar ([@DharmikSondagar](https://github.com/DharmikSondagar))
- Kamil Mysliwiec ([@kamilmysliwiec](https://github.com/kamilmysliwiec))
- Lazizbek Ergashev ([@lazerg](https://github.com/lazerg))
- Luke Son ([@KAPUIST](https://github.com/KAPUIST))
- Micael Levi L. Cavalcante ([@micalevisk](https://github.com/micalevisk))
- Roman Khegay ([@thekhegay](https://github.com/thekhegay))
- Suliman Abdulrazzaq ([@SulimanAbdulrazzaq](https://github.com/SulimanAbdulrazzaq))
- Xia Chao ([@xia-chao](https://github.com/xia-chao))
- [@erezcor](https://github.com/erezcor)
- fadi romdhan ([@fadiroot](https://github.com/fadiroot))