“tabcmd” can’t be opened because Apple cannot check it for malicious software.

[lynchypin]

I have tried several times and I keep getting the same message, is there an updated version somewhere/ in development?

[jacalata]

We need to submit the app to Apple for 'notarization' in order to stop that error. Unfortunately there is some internal process around having to sign the executable and submit it to Apple, and I can't give an estimate of when we will have a notarized version to run. (https://developer.apple.com/documentation/security/notarizing-macos-software-before-distribution)

Until then, if your IT setup allows, you should be able to right-click the app and select 'Open' to deliberately accept the warning and open the app.