Coffee GB v2.1.3 is released. Coffee GB is a Gameboy Color emulator written in Java 16 (core) and Kotlin (UI). It's meant to be a development exercise.

Features:
Full support for GB & GBC emulation.
Partial Super Gameboy emulation (borders and palette).
Cycle-exact CPU emulation. Each opcode is split into a few micro-operations (load value from memory, store it to register, etc.) and each micro-operation is run in a separate CPU cycle.
Quite compatible (all the Blargg's tests are passed, although some game still doesn't work)
Rollback-based netplay
MBC1-5 support
Battery saves
Support for zipped ROMs
ROM-based compatibility tests run from Maven

Coffee GB Changelog:
Coffee GB 2.1.3 fixes multiplayer Link Mode in Razor Freestyle Scooter. In-process link partners now exchange each peer's live serial bit synchronously, and the fast Game Boy Color role-election lead ends as soon as one console becomes the listener. This restores the two-player Racing and Trick Mode selection while preserving existing save-state and non-peer serial-device behavior.
Merged pull requests
#664 — Fix Razor Freestyle Scooter multiplayer link by @trekawek
Fixed issues
#663 — Razor Freestyle Scooter cannot choose Multi-Player, reported by @ScottNash042 and fixed by #664
Non-PR changes
None. All non-mechanical changes in this release range are represented by the merged pull request above; Maven version-transition commits are omitted.
Visual compatibility fix
Razor Freestyle Scooter Multi-Player Racing and Trick Mode menu
The Multi-Player Racing / Trick Mode menu after the link fix for #663.
Known platform limitations
On macOS, game controllers require a compatible system SDL2 installation; keyboard input and emulation remain usable without it.

Download: Coffee GB v2.1.3
Source: Here