Although this approach may seem prone to abuse (e.g., improper use of GPL code), our experience has been that companies tend to be risk-averse and prefer purchasing proper licenses to avoid violating a copyleft license. A successful example of this strategy from outside of proteomics has been RStudio by Posit. RStudio is currently available under an open-source AGPLv3 license, or under a commercial license when AGPLv3 is incompatible. Notably, developers should make sure to include a "contributor license agreement" as part of their requirements for new contributors to ensure their contributions can be distributed under both licenses.