It is true.
Heat evolved/released(System) = - Heat evolved/released(Surrounding)
Heat absorbed(System)= +Heat absorbed(Surrounding)
So if you consider one thing (say System)
to be of positive sign convention then other thing (Surrounding) becomes
negative in sign convention
In physics we give more importance
to System. For example we calculate forces, acceleration, velocity etc
of a body which constitutes System. Hence System becomes reference in
physics. So we give positive sign convention for System.