[BUG] Minecraft 1.21 causes UnsupportedClassVersionError

[Supermarcel10]

• I searched the issue tracker for other issues covering my case
• This is a Launcher issue. (Usually if you can reproduce it with a fresh instance)

Describe the bug
An UnsupportedClassVersionError is thrown during startup of vanilla Minecraft 1.21.

To Reproduce
Steps to reproduce the behavior:

1. Open GDLauncher
2. Install Vanilla 1.21
3. Run

Expected behavior
No error is thrown

Possible solutions
Update the launcher to use JDK21 in order to support Minecraft 1.21. It currently seems that GDLauncher assigns JDK17 despite JDK21 installed and present on the system.

It's possible to currently overcome this by simply setting "Custom Java Path" in Properties to JDK21.

Screenshots

Operating System:

• OS: Windows 10 22H2
• Launcher Version: 1.1.30
• Java Versions:
  • 1.8.0_312-b07
  • 17.0.1+12
  • 21.0.3+7-LTS-152
• Minecraft Version: 1.21
• Mod Loader: N/A

[OttCS]

Gorilla Devs are no longer working on this version on the launcher (last release was a year ago), but they have a new one with TONS of bug fixes from the past year (as well as support for 1.21): https://github.com/gorilla-devs/GDLauncher-Carbon. If you have the same problem, report it in that repo.

[Supermarcel10]

@OttCS thanks for the heads up, I wasn't aware.

Maybe worthwhile making a final update to this stale repository, like a notification or update prompt of some sort for people to move to Carbon?

[blarfoon]

Will do it shortly, most likely this week. I've been very careful about not forcing or endorsing the new app to much until it was stable enough. For most people the first feedback is often the final and it was very important to not drive people away because of early bugs.