Works without breaking into elgg 2.3.0 ??

Elgg 2.3 should be fully backward compatible regarding plugins, i.e. it should work on 2.3 if it is recommended for 2.2.

Hmm, Elgg 2.3 is not fully BC compatible. The file structure changed. Uploading files is not guaranteed to work. For instance I had to make a 2.3 only version of webcam in order to get profile pictures uploaded. which worked for 2.2 and older versions.

Other significant change I noticed is how urls are hashed, 2.3 uses a different approach (HMAC) and again one of our plugin's (validation reminder, which sends out notifications to users reminding to validate their account) was broken.

Don't cry over the spilled milk. Participate in the review process for open PRs to prevent BC issues with use cases that are atypical. Open an issue for any introduced BC issues, submit a PR to rectify the situation etc. It's impossible to know what weird things people are doing with the Elgg code. All PRs have been peer reviewed so if there are BC issues than the plugins are doing something that none of us on the team have had to deal with in a decade of working with Elgg.