If you really want to use it with Diplomacy, you'll have to add the line "allegianceDecreasePerRoundtrip 0.000" (0.0 can be changed to whatever) to all of the frigates/cruisers, use a different Gameplay.constants, update the Strings file (aka. add in the new strings Diplomacy uses), plus get the whole Envoy tech tree working. It isn't too hard to upgrade to Diplomacy, I could easily make a working Gameplay.constants and add the line, the tech would take time however. Though atm I'd much rather get the Entrenchment version done first, and I believe that it's fairly close to completion, NR frigate fleet notwithstanding.