samsung smartphone having exynos 7 octa processor or above including mid range phone supports 2CA feature. but some user are confusing why 4G+ icon is not showing in status bar. it is because of software update but it doent mean ur smartphone not supporting CA feature. If u want to check whether ur phone supporting CA feature or not..u can use netmonster app from google play. which will clear your doubt. this application will show you real time frequency band of ur network operator.
no bro he is correct j7 prime with 7870 has dual band cat4/6 modem and it supports CA in upload but not in download. i checked Ue capability of that and in that device MiMo supports in UL not in DL. thats the reason netmonster app shows CA though not added & shown in status bar.