This release brings a few bug fixes and under-the-hood improvements.

The main user-facing change is the deprecation of user-configurable IsFatal. We decided to deprecate this feature as we believe it's not a feature used by many users (if any) and supporting it brings a lot of unnecessary complexity to ZIO's codebase. If your codebase / library is affected by this change, please open an issue with your use-case.

What's Changed

• Enable build tools to relocate "target/test-reports-zio/output.json". by @dubinsky in https://github.com/zio/zio/pull/10054
• Deprecate ZIO::catchNonFatalOrDie by @guizmaii in https://github.com/zio/zio/pull/10052
• Optimise FiberRef::modify by @guizmaii in https://github.com/zio/zio/pull/10041
• Make Chunk::Singleton more lightweight by @guizmaii in https://github.com/zio/zio/pull/10066
• Optimize ZChannel code: Remove ZIO::unless usages by @guizmaii in https://github.com/zio/zio/pull/10058
• Optimise Chunk: Remove some Some allocations by @guizmaii in https://github.com/zio/zio/pull/10067
• Optimise Trace.toJava by @guizmaii in https://github.com/zio/zio/pull/10091
• Make some Chunk implementations more lightweight by @guizmaii in https://github.com/zio/zio/pull/10078
• zio-test: Improve rendering of Tuples by @guizmaii in https://github.com/zio/zio/pull/10098
• Optimise Hub code by @guizmaii in https://github.com/zio/zio/pull/10094
• Fix laziness of ZStream::paginateChunk by @guizmaii in https://github.com/zio/zio/pull/10113
• enable ZIO Signaling with GraalVM Native Image - related to #9240 by @jamesward in https://github.com/zio/zio/pull/10115
• Optimize ZPipeline::mapEitherChunked by @guizmaii in https://github.com/zio/zio/pull/9816
• Hub: Prefer ZIO over Exit in .onInterrupt calls by @guizmaii in https://github.com/zio/zio/pull/10126
• Optimise ZStream.fromIteratorSucceed by @guizmaii in https://github.com/zio/zio/pull/10083
• Do not log an interruption error on app shutdown by @kyri-petrou in https://github.com/zio/zio/pull/10141
• Deprecate IsFatal in preparation for removal by @hearnadam in https://github.com/zio/zio/pull/10140
• Make TestArrow.run stack safe by @hearnadam in https://github.com/zio/zio/pull/10138
• [test-sbt] More uniformity. by @dubinsky in https://github.com/zio/zio/pull/10120

Other changes (CI, dependencies and documentation)

• fix(deps): update dependency @zio.dev/zio-telemetry to v3.1.7 by @renovate[bot] in https://github.com/zio/zio/pull/10033
• Update junit-platform-engine to 1.13.4 by @zio-scala-steward[bot] in https://github.com/zio/zio/pull/10040
• Update spring-core to 6.2.9 by @zio-scala-steward[bot] in https://github.com/zio/zio/pull/10032
• fix(deps): update dependency @zio.dev/zio-quill to v4.8.6 by @renovate[bot] in https://github.com/zio/zio/pull/10031
• Update maven-compat, maven-embedder to 3.9.11 by @zio-scala-steward[bot] in https://github.com/zio/zio/pull/10029
• Update reactor-core to 3.7.8 by @zio-scala-steward[bot] in https://github.com/zio/zio/pull/10028
• Update snakeyaml-engine to 2.10 by @zio-scala-steward[bot] in https://github.com/zio/zio/pull/10026
• Update sbt-ide-settings to 1.1.3 by @zio-scala-steward[bot] in https://github.com/zio/zio/pull/10025
• fix(deps): update dependency @zio.dev/zio-redis to v1.1.5 by @renovate[bot] in https://github.com/zio/zio/pull/10046
• Improve Scalac configuration: Disable auto-tupling for Scala 3 by @guizmaii in https://github.com/zio/zio/pull/10043
• Update cats-effect to 3.6.3 by @zio-scala-steward[bot] in https://github.com/zio/zio/pull/10049
• Update scalajs-dom to 2.8.1 by @zio-scala-steward[bot] in https://github.com/zio/zio/pull/10048
• fix(deps): update dependency @zio.dev/zio-dynamodb to v1.0.0-rc20 by @renovate[bot] in https://github.com/zio/zio/pull/10047
• fix(deps): update react monorepo to v19.1.1 by @renovate[bot] in https://github.com/zio/zio/pull/10056
• chore(deps): update dependency cytoscape to v3.33.0 by @renovate[bot] in https://github.com/zio/zio/pull/10057
• chore(deps): update dependency @types/react to v19.1.9 by @renovate[bot] in https://github.com/zio/zio/pull/10059
• Add test for ZStream.fromIterator about exceptional case by @guizmaii in https://github.com/zio/zio/pull/10062
• Update sbt-bloop to 2.0.12 by @zio-scala-steward[bot] in https://github.com/zio/zio/pull/10064
• fmt by @guizmaii in https://github.com/zio/zio/pull/10065
• chore(deps): update dependency typescript to v5.9.2 by @renovate[bot] in https://github.com/zio/zio/pull/10072
• Mention Gradle plugin for Scala.js and Scala Native. by @dubinsky in https://github.com/zio/zio/pull/10053
• fix(deps): update dependency @zio.dev/zio-schema to v1.7.4 by @renovate[bot] in https://github.com/zio/zio/pull/10076
• Update sbt, sbt-dependency-tree, ... to 1.11.4 by @zio-scala-steward[bot] in https://github.com/zio/zio/pull/10077
• Update sbt-bloop to 2.0.13 by @zio-scala-steward[bot] in https://github.com/zio/zio/pull/10086
• fix(deps): update dependency @zio.dev/zio-ftp to v0.5.1 by @renovate[bot] in https://github.com/zio/zio/pull/10089

Full Changelog: https://github.com/zio/zio/compare/v2.1.20...v2.1.21