Sorry for my inexperience on Mikrotik but wish if someone may help me on filtering issue I have.
I am using Winbox v6.40.6. I would like to put an IP Firewall Filter rule that will force a particular PC with Mac address 18:31:BF:69:9B:8E to be disallowed any type of internet connection (including Skype, Discord, Messenger and games) from 12:00:00 to 16:00:00 everyday except for Spotify music
Unless you know how to code for spotify music at layer 7, me thinks its an all or none proposition.
Also why not fix that mac address to an IP address (static assignment) and then block by IP)