Some bouncers need to have the chat history replay set to enabled, some clients need a plugin to replay the history. I use Soju+weechat and had to do a bit of configuring to get it to work, but now it does work fine. Also, some channels have a server side history replay enabled, for example, in our network the main channel replays automagically 15 last messages and you can do a command to replay the last 100 messages.

Mobile support has improved a lot lately. There is a couple of users on the network who only use mobile to chat. Personally I don’t use any, so I can’t say much about it.