Boolean or int type for app to controller button input

Docs say to use int, but I may have got it working with boolean type some time ago. Neither work anymore! Does it HAVE to be int type?

Could you please provide more details? It is not clear for me what do you mean

int tank1PreferenceButton = 0;

or should it be:

boolean tank1PreferenceButton = 0;

BLYNK_WRITE(V2){ // Assign virtual pin V2 to tank 1 preference button on Blynk app widget.

tank1PreferenceButton = param.asInt();