Do racial weapon strengths automatically update?

[NuclearStudent (OP)]

When I research the next tier of racial weapons's strength (whatever that might be), do old ground units automatically get the benefit of that research? Or do I need to research new units and build those instead? Also, is armor strength retroactive as well?

[Conscript Gary]

Nope. A ground unit's stats are locked in at the time of research.

[Father Tim]

When I research the next tier of racial weapons's strength (whatever that might be), do old ground units automatically get the benefit of that research?

No.

Or do I need to research new units and build those instead?

Yes.

Also, is armor strength retroactive as well?

No.