[Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).

This error happened if you are updating from MySQL 5.5 to MySQL 5.6 or when are using data folder that was on 5.5 server on 5.6 server . 

Anyway the solution is very easy and it is just a Warning but it is great to clear such things when you found it on your event log file.

 Add this line to MySQL configuration file , my.cnf or my.ini :

 explicit_defaults_for_timestamp = TRUE 

 restart your MySQL server and check your events log file.