New version's lowercased name issue

[spello]

Hello. I've upgraded from phpBB 3.1.x to phpBB 3.3.8 and I have a problem. I haven't removed data of ext version 2.0.2. Before upgrade I had only removed extension's files and now on ext version 3.0.0-dev I see double entries because the old one was named rxu/PostsMerging and the new one is lowercased (rxu/postsmerging). I haven't activated this extension on phpBB 3.3.8 yet. What sould I do? Should I change some values on database to fix this issue?

[rxu]

There's no upgrade path from the extension branch 2.0.x to 3.0.x. The only way is to fully delete/purge 2.0.x extension ang then install 3.0.x from scratch.
Also please note that 3.0.x is an unreleased development version so there's no actual user support for it.