This list could be a helpful starting point: https://en.wikipedia.org/wiki/Comparison_of_cross-platform_instant_messaging_clients https://en.wikipedia.org/wiki

This list could be a helpful starting point: https://en.wikipedia.org/wiki/Comparison_of_cross-platform_instant_messaging_clients https://en.wikipedia.org/wiki/Comparison_of_cross-platform_i... You can sort the table by clicking on the column headers. The "E2EE group chat" column should be useful.