Nextcloud mail is unusably slow AND saves every single email in the database with no pruning, for the joy of a sysadmin that will see the database growing growing growing (from my experience a couple years ago, didn’t try extensively recently)
Roundcube instead is fast and easy to install but much limited. Everything is a PHP plugin developed by someone else who might abandon it at any time and I don’t really like that. Default install is barebones and has less features than outlook express on windows 98.
Almost a decade ago they did a crowdfunding to rewrite it, but it was abandoned , latest commits here https://github.com/roundcube-next
I've been looking for a round cube replacement for years and can't find one. It's the only mature and still relatively supported FOSS web-based solution I've found that fits my requirements.
I'm praying that nothing changes but fully expect it to. I'm going to maintain a fork just in case decided to pull an Audacity.
Yeah, snappymail is what I found as the best alternative that fitted my criteria (docker install and unified inbox).
Quickly checked out Afterlogic webmail lite, but I am not sure if it does unified inbox?
Unified inbox for afterlogic is enabled only with the pro license (it's still technically open source since it's PHP, but you're not licensed to redistribute it)