I have observed that majority of Samsung M51 users have complained of slow internet speed and have been tirelessly demanding Carrier Aggregation support to resolve the issues. Samsung has surely listened to its users and provided some great features through updates from time to time. But it is this "MOST SOUGHT FEATURE" that the Samsung has failed us time and again. Lately Samsung has only provided security update (with some unwanted apps and bloatwares).
I request Samsung again to provide Carrier Aggregation support for M51 as this is the most vital one and will probably solve the major issue of low network connectivity.