I purchased PDF Architect 2.0 and several modules. Later on, I downloaded version 3.0. I started using 3.0 but realized I had to re-purchase the same modules, much to my chagrin. I’m considering upgrading to 4.0. Do I have to repurchase the modules each time there is an upgrade?
yes since the licenses are always lifetime and there is no subscription model, the main version updates always require a purchase. When you purchased the standard or pro package, you will get offers to upgrade at a reduced price. I am afraid there is no discount for single modules though.
It is possible to install multiple versions of PDF Architect on the same machine and e.g. using only the free modules for PDF Architect 4 and keeping PDF Architect 3 for the purchased modules.
Only main version upgrades require a purchase, upgrades from e.g. 4.0 to 4.1 are always free.