Research needed to build: Invention (Science)
Purpose: Purchase offensive/Defensive upgrades for unit(naval and land)
Build in more then one town: Just need one to upgrade all units, can build in multiple towns for multiple upgrades at once.
Soft Cap: lvl 24 Can build higher but after 24 the cost is greatly increased. However only lvl 8 is needed to obtain all upgrades possible.
General Information regarding the Workshop
Lets take a look around the window from the Workshop's view(once you click on your on the Workshop)
On the left side of the screen you will see
Here you can see how much materials will be needed to upgrade and how long it will take. Also you have the option to demolish the building as well. Clicking demolish will give you a confirmation screen showing how much resource you would recover. This option is helpful for when you want to abandon a colony and recover some of the luxury resources and wood.
Now in the middle of the screen you will see two tabs:
--Click for ground troop upgrades.
--Click for naval upgrades
In the middle you will see something like the following:
Here you will see what upgrades you can currently buy, how much gold and crystal are needed and how long it will take.
Upgrades in one workshop carry over to all troops in your empire. They also stack, so if you train a +2 offense and a +2 offense to slingers you will have an extra +4 offense bonus for them.
Also you must have all the crystal in the colony needed to upgrade a unit. For this reason some will build the workshop on their crystal producing colony if they have one.
As of patch v0.2.7 any troop with an offensive upgrade do not get receive the 10% attack bonus for each breach in a town wall. However if they have defensives upgrades they still receive the attack bonus.