And just to reinforce the point, I am flying 3 planes right now with 2S Fromeco Relions with the 6014HS receiver. Zero issues. With any of the Futaba receivers it is your servo voltage that is the true limit on voltage you use. All Futaba 2.4 receivers can handle unregulated 2S lipos/2S Lions with no issues at all.
Bill M.
Team Futaba
Orange County, CA