Under older versions of GC4, whenever you researched the tech for a larger class of ship, the game would automatically generate ungraded, larger ship designs - which would show up in your shipyard buildable model list.

This may have also occured when a new tech gave upgraded capabilites - for example better armour or shields.

I do not see this feature, with V 2.2. Was it removed, or am I missing a setting in Options?

I researched Frigate hulls, but the only ships listed in my build list were tiny ones. However, I was able to go into the Ship Designer to build a new Frigate from scratch.