Its business model and not requiring a phone number

Why Threema?

Currently limited to groups chats of 256 participants and group calls of 16 participants

For privacy, freedom, and control, iOS is out. As with Telegram, I advise staying away from the Google variant and highly recommend the Threema Libre implementation for Android. Licenses are not compatible across variants, so stick with the Threema Shop!

• Open source full E2EE (end-to-end encryption) platform with regular security audits
• Mobile clients can be linked to Threema Desktop/Web
• Source code available for Android, iOS, Desktop, and Web
• Threema Libre implementation for Android
  • Liberated from Google Services, uses Threema Push for instant delivery
  • Reproducible builds
  • Available via F-Droid repository
• Simplified (normal human-understandable) Changelog
• Multiple ways to purchase through Threema Shop
  • With or without Email Address
  • Cash, Bitcoin, Mastercard, Visa, or bank transfer - Can leave every non-payment field blank!
  • 4.99 CHF, EUR, or USD per license
  • Pay anonymously with cash (rounded nearest 10, buy in multiples of 2)

The largest criticism levied against Threema:

• 2023010? - Accusation - Three Lessons from Threema - Analysis of a Secure Messenger
• 20230109 - Rebuttal - Statement on ETH Findings
• 20230110 - Coverage - Messenger billed as better than Signal is riddled with vulnerabilities

“While some of the findings presented in the paper may be interesting from a theoretical standpoint, none of them ever had any considerable real-world impact,” the post stated. “Most assume extensive and unrealistic prerequisites that would have far greater consequences than the respective finding itself.”