I noticed last night that one of my opponent's ships' kept increasing in attack power, without buying new ships. It was the Yor I believe, and his escorts continually increased in power as they sat along side my border. I tried to find a way to do this myself but it seemed the only way I could do it was to upgrade the ship design to something with better weapons, but since you can’t upgrade a core ship design I was left building a new ship and having to pay a ton of money to change it into a new ship to match his firepower.

I’m not sure what I’m missing here, as I’m pretty new to the game. (Luckily I was a diplomat anyhow and won by alliance and It didn’t come down to fighting him, but I would have been destroyed if so.)