Thanks to Jorge for sending me this.
Quoting DarthDoge:
I have been in contact with Sub_Octavian for about a week. Yesterday, I inquired about if we could have the forum message capacity increased or if I could apply as being a clan recruiter with a 50 msg capacity is kind of annoying. I was surprised when he said he’ll contact the team.
I then got confirmation three hours ago that it was increased, I checked and now it’s 250 messages cap… amazing! This makes it for people that need to send many messages out there much easier.
Thank you Sub_Octavian!
Also I checked, and the inbox message storage is only enlarged for the NA WoWS forums. Not on EU WoWS or any WoT forums. Quite a shame.