Sorry for the delay, somehow I missed your email. I've updated Showdown to the latest version.
And I don't think it was a memory issue. If 50 days of uptime causes Showdown to run out of memory then they have a serious problem with memory leaks!
Edit: wait just remembered that my host were updating and rebooting all the servers over the past couple of weeks. I made sure to check PokemonDb when they did it but forgot that I would need to restart Showdown when they rebooted that server. Sorry :/