Tech upgrades are unlocked once the Auxesia is bought, in this new menu you'll be able to buy two tech upgrades per generator tier.
These are separated in:
Hardware Upgrades[]
Hardware upgrades increase the output of the accompanying generator tier by 10% per level.
Software Upgrades[]
Software Upgrades increase the output of the accompanying generator tier by 1% for each manually purchased generator in that tier per level.
Tech upgrades also have a role in some bonuses, such as a Loop Modification (eg: Tech Softwarwe Scaling Module MK1,) that increases cells gained by 0.5% per Software upgrade level (additive).
The final output of software and hardware tech upgrades can be raised from several places, such as from the Auxesia itself and some installs from the Hephaestus.
*Since it is specifically the final output and not the bonuses themselves, they are not reflected in the hardware and software descriptions. They will still stay at 10% and 1% per manual generator, respectively.