Red CTAs, once again

The app I'm working on is using red CTA buttons. We use one CTA/screen (or at least that's what we do since I joined).

I have now people questioning how effective red CTA buttons are. We don't have an a/b testing tool right now and I don't want to make the devs change the CTA in android or iOS just to test that.

Does anyone have any solid research on CTA buttons in mobile apps that are used exclusively and not against other colours?