Hello again @TaupeAphid6383! Allow me to correct myself from that earlier post;
Outlaws gain 20% (up from 15% for regular units) for Fortress/Veteran, when you research Folk Heroes or equivalent
Outlaws gain 25% (down from 30% for regular units) for reaching Industrial age (This is a free auto upgrade)
Outlaws gain 50% (same as regular units) for reaching Imperial age (This is a free auto upgrade)
This is intentional, as 5% from Industrial has been allocated to Fortress instead.
Hope this helps!
Thanks for reply again, but for regular units, the Fortress/Veteran upgrade is also 20% not 15%, so it’s less 5% than normal units. Please check it again. It should be 25%(III) + 25%(IV) +50%(V). Thanks! @gmenyhart