• Minecraft Version: 1.11.2
• BetterFps Version: 1.4.3
• Forge/LiteLoader Version (if any):
• Crash Logs (if any):
• Other Mods (if any):

When installing BetterFPS to the vanilla launcher, it is not detected as a version, therefore isn't available. Tested on Windows 7, Windows 10 and Ubuntu 16.04 (All 64 bit)

Do you have Minecraft vanilla 1.11.2 installed?

Yes, I do. Also, it doesn't seem to matter whether I have OptiFine on it or not. Extending from OptiFine or Vanilla 1.11.2, neither work. I also tried renaming the folder, json and the id inside the json of the version, but it still isn't showing up and I have no idea why.

Are you using the new launcher or the old (java) one?
Which process is not working? The part of the installer where you choose the version to install?

Well on Ubuntu I have no choice, but on all 3 tests, it was with the old Java launcher. Also, installing it works fine, just that AFTER it's installed, the launcher isn't detecting the version installed.

I've just found the problem: The old launcher doesn't know how to parse all of ISO 8601 date formats, while the new launcher does.

Format that I was using: 2017-04-22T19:39:47
Format that the old launcher accepts: 2017-04-22T19:39:47-0300

Yeah... Just because of five extra characters in the date, the installer isn't working in the old launcher. I'll release a new version with the fix tomorrow :)

I'll release a new version with the fix tomorrow :)

...and I've never released.
Sorry, I totally forgot about it. It's out now