Hello,

AFAIK current largest supported map size is 7168 x 4096. I am just curious, how hard would be to increase this limit? Obviously it would require significant changes on client, but my question is from the server point of view. Would it require some serious refactoring of server systems, or changes shoudnt be that hard? Thanks for any insights.

I don't know of any limitations in POL. You might want to keep the size divisible by 8x8.

And if I recall correctly, some clients even accept larger map widths as long as you keep the height 4096

The Classic UO third party client accepts larger map sizes.
https://www.classicuo.eu/