v4.0.0-alpha-15

What's Changed

Fixes & Enhancements

• Fix IllegalStateException in SchedulerToExecutorService.invokeAny by @vasiliy-mikhailov in #8159
• 4.x: API turn Completable concatX and mergeX into config-based by @akarnokd in #8166

Cleanup

• 4.x: Unit test lambdaification 14 of N by @akarnokd in #8155
• 4.x: Unit test lambdaification 15 of N by @akarnokd in #8156
• 4.x: Unit test lambdaification 16 of N by @akarnokd in #8157
• 4.x: Unit test lambdaification 17 of N by @akarnokd in #8158
• 4.x: Unit test lambdaification 18 of N by @akarnokd in #8160
• 4.x: Unit test lambdaification 19 of N by @akarnokd in #8161
• 4.x: Unit test lambdaification 20 of N by @akarnokd in #8162
• 4.x: Unit test lambdaification 21 of N by @akarnokd in #8163
• 4.x: Unit test lambdaification 22 of N by @akarnokd in #8164
• 4.x: Unit test lambdaification 23 of 23 by @akarnokd in #8165

Chores

None

Full Changelog: v4.0.0-alpha-14...v4.0.0-alpha-15