Some firewall rules were changed after the upgrade.

All of my X86 router’s SPI firewall rules were changed after the upgrade. I do not know when or what version I had before.

Before upgrade.

/ip firewall filter
add chain=forward protocol=tcp connection-state=invalid \
 	action=drop comment="drop invalid connections"  
add chain=forward connection-state=established action=accept \ 
 	comment="allow already established connections"  
add chain=forward connection-state=related action=accept \
 	comment="allow related connections"

After the upgrade.

/ip firewall filter
add chain=forward protocol=tcp connection-state="" \
 	action=drop comment="drop invalid connections"  
add chain=forward connection-state="" action=accept \ 
 	comment="allow already established connections"  
add chain=forward connection-state="" action=accept \
 	comment="allow related connections"