Surprise! Samsung is now rolling first One UI beta update to the Galaxy A7 (2018) users that bring several features improvements. It includes the February 2019 security patch. The update is now available in India.
The update is currently rolling out with build version A750FXXU1ZSB4. While the size of the update is 1322.48 MB.
After successful beta registration, go to Settings and then Update Software to select the Download Updates Manually option. This will allow the software to update and load the beta version.