Greetings m'lord!

I don't think they do, however, they do increase the repairing speed of the construction once destroyed.

I believe that the Townhall does speed up the upgrade process, though!

ok thats a good answer probably this is what means the instruction about summoners but it is nt completely clear if it means just the repairing speed or upgrading i guess it is this you say,any one else is more sure about it let me know