A few questions about how unit upgrading works.

[ShadowXOR]

How do you enter a new "era" and become able to build the upgraded version of units...like a tank instead of archers or whatever the equivalents are?

And whenever you do whatever is required, do older units get upgraded into their new form, and if not can I do that manually somehow?

And somehow it occasionally offered to make my unit one of two different options giving them a bonus like towards attacking or defending cities, but it always gave two options and seemed random, are they random? If I wait until my next turn do I get different upgrade options? Thanks.

[PhillyMike101]

How do you enter a new "era" and become able to build the upgraded version of units...like a tank instead of archers or whatever the equivalents are?

And whenever you do whatever is required, do older units get upgraded into their new form, and if not can I do that manually somehow?

And somehow it occasionally offered to make my unit one of two different options giving them a bonus like towards attacking or defending cities, but it always gave two options and seemed random, are they random? If I wait until my next turn do I get different upgrade options? Thanks.

Older units stay older unless:

1. Youre Germany and those units are Elites. They then get auto upgraded.
2. You build the Leonardo's Workshop Wonder (Invention). It is a one time only upgrade for all your units.

Im pretty sure they are random, and I dont think you get different options. Once you press 'Y' or Triangle you get what you get, I believe. You get that option once your unit has won 6 battles (If you built them from a city without a barracks) or 3 battles (If you built them from a city with barracks). That makes them 'Elite' units. When you build a barracks and then a unit from one city, they become veterans and need 3 more wins to become elite. If you build them from a city without a barracks they need 3 wins to become veterans and then 3 more wins to become elite.

[ShadowXOR]

Thanks for the info, you missed one though. How do I progress to a new era and how do I get the ability to build the upgraded units? Thanks.

[Sigmakan]

Technologies.

You need to research a certain amount of techs to advance eras:

Ancient - 0 techs
Medieval - 5 techs
Industrial - 14 techs
Modern - 24 techs

To build new units you need to research the appropiate technology. For example, tanks require the technology Combustion.

[ShadowXOR]

Thanks for the great info! I hope the instruction book covers some of this stuff because the demo tutorial left me clueless!!!