Open admission of funding from Village Global, which is owned by Microsoft,
https://simplex.chat/blog/20230422-simplex-chat-vision-funding-v5-videos-files-passcode.html

Further on pitchbook, they list the Village Global investment,
https://pitchbook.com/profiles/company/528431-50#signals

When asked about it, the lead dev Evgeny Poberezkin said yes it's true, microsoft