4,000,000 Square Feet = 37.161216 Hectares

4,000,000 Square Feet = 0.37161216 Square Kilometers

Most clients also offer OpenPGP which has the properties you are looking for.

Are you talking about omemo and a scenario where you buy a new device and want to sync your entire history from the server?

Skip the blog spam right to the maintainer’s announcement

If you use Linux in English, en-CA is also the best locale to use, it has 24 hour time, metric units and simplified (american) language. They will conquer the world with convenience!