Why can't i send composition from After Effects CC 2014 to Media Encoder CC 2015??
i don't wanna waste my time waiting to finish rendering first composition when i have other compositnion unfinished
That is to be expected. All DynamicLink functions require the same version level. Only CC 2015 stuff will render in AME 2015.
so i must upgrade to After Effects CC 2015? if yes, then will it cost me somethimg or upgrade is free?
If you are a subscriber to the Creative Cloud, your subscription includes all versions of all of Adobe's creative software from CS6 onward. This includes CS6, CC, CC 2014, and CC 2015.