Threema’s business model relies on a one-time purchase to fund its independent infrastructure in Switzerland, avoiding the need to sell user data. Utilizing pirated versions starves the developers of the resources needed to maintain the servers that facilitate the secure routing of messages. Furthermore, official features like (encrypted backups) and push notifications often fail to work correctly in modified versions because they lack the necessary signatures from Apple’s servers. Conclusion

Secure messengers require frequent patching to address newly discovered vulnerabilities. A static, sideloaded IPA quickly becomes obsolete and insecure. Ethical and Functional Implications

The distribution and use of modified application files, such as the Threema IPA referenced in your topic, represent a significant intersection of digital privacy, cybersecurity, and software ethics. While Threema is renowned for its "security by design" philosophy and commitment to metadata minimization, obtaining the app through unofficial channels introduces risks that can undermine those very protections. The Appeal of Sideloading

Unofficial binaries can contain spyware or keyloggers that monitor the entire device, not just the app itself.

There is no guarantee that the encryption libraries have not been tampered with. A "man-in-the-middle" or back-door could be injected into the code, allowing a third party to intercept messages before they are encrypted.