The recent news about WhatsApp's privacy policy is concerning, particularly for me working in the cyber security field. I have been using Signal (and before that, TextSecure) for many years and have been looking for a reason to get rid of WhatsApp ever since Facebook bought it. I don't trust the company at all and there are good reasons why WhatsApp is not approved as a secure way to communicate with Australian Government agencies. Historically the only reason I kept it was because it was more popular among users when compared to Signal, but that has been changing (particularly in the last 6 months or so).
For those who don't know, beginning next month (February 2021), WhatsApp's privacy policy changes and will be forced on all users. There is no way to opt out (at the time of writing this). I'm not going to dissect every bit of their policy (you can read the entire thing at
https://www.whatsapp.com/legal/updates/privacy-policy/?lang=en but here are the key points):
From next month, WhatsApp will
"share your information to help (them) operate, improve, understand, customise, support and market services". This includes: Information associated with your account, such as phone number, profile name, photo, about information, last seen information, message receipts, information about your contacts (such as phone numbers), transaction and payment data. This information is used by Facebook themselves, "other Facebook companies' and third-parties they do business with.
This might not concern you, but it concerns me.
Signal Private Messenger which is available for both iOS, Android and desktop operating systems (including Linux). It has all the features of WhatsApp (and then some), has been independently security audited (and vetted by some agencies I work with) and best of all, it even replaces your default SMS application entirely as it handles both encrypted messaging and insecure SMS messages (if you choose to or if the user does not use Signal). I personally use the one application for everything including secure voice and video calls (since 99% of my contacts also use it).
https://signal.org/en/Highly recommended.