To continue development of unsupported/abandoned plugin
Check the licensing and make sure everything’s legit, fork the code, apply new license, include existing license(s) as necessary, apply patch from @gravitylover and re-release as a new plugin. Steps may vary. Check the actual LICENSE
or COPYING
file for specific requirements. These should be included in every repository.
For God’s sake, if you release a plugin, be sure to either omit the version or include the -or-later
clause to ensure future license compatibility if licensed under GPL. This will require reading the GNU website top to bottom. Be sure to also check the FAQ and compatibility matrix. This is a rite of passage.
Check opensource.stackexchange.com for open source licensing questions. Be absolutely sure if you release a new plugin you’re ready to assume responsibility of supporting it or an angry mob will come after you with pitchforks and molotov cocktails in hand and no holds barred.
There may be other ways to do this, such as a transfer of ownership. In that case you’ll want to check with the plugin author first, or, if they cannot be reached, contact the WP plugin team via email or Slack for next steps.