I'm working on a mod that will allow the player to gain access to improved versions of their standard techs as they progress through the story. Since I want the mod to be relatively painless on the user side, I wanted to have a separate (but easy) quest that will unlock the new techs, in case that character has already completed that story quest. This gave me the idea of requiring the player to actually obtain previous techs in order to complete said quest. However, I'm having a hard time figuring out how to even tell what techs the player has. Are they just items secretly hiding within the player's inventory, like pixels?
As for making it more painless while giving you lots of options to control when and how they get unlocked, I made this. Requiring a certain quest is an option (you can choose completed, or accept active quests too). Or if you want to use universe flags (any player unlocked it), that too is an option. Requiring other techs be enabled is supported - which means you can do a sequential unlock. "numbah90_multiJump3" requires "numbah90_multiJump2", etc. As for an active example, I do so in my own tech mod (which actually has the tech helper stuff baked in and thus functions as an alternate prerequisite). Having that tech available (no requirement that they paid to enable it) is also an option. You can require alternative materials, include only certain races, exclude certain races, and more. So if you wanted a better versions of the aqua sphere for Hylotl (while denying them access to the inferior line), you can do that. If you want a feature that isn't there, I can add it. If you have questions, let me know. Ah speak of questions, I should answer your direct question.