How do we share our city upgrades to the region?
Solution 1:
It may still be a server issue, even my private game with no external players is not syncing instantly like it should. Townhall addons when placed apply to the region automatically same goes for the HQ for specializations (usually), there is nothing more that you need to do
Solution 2:
Be aware that larger maps are actually composed of multiple smaller regions. Your Town hall upgrades are shared with 3 or 4 other specific city plots - not all 15.