Are you using Webex Calling platform for calling functionality? Is the call transfer working on desk phone?
A few other customers have also reported this issue which is being investigated by our engineering team. In the interim, you might want to download the previous version (41.9) from Control Hub. Click on Messaging > Webex app software release management >Available builds for testing > click Builds available for download. I've attached a screenshot for your reference.
We do not have access to a control hub. Our app was provided through a vendor "The One Point". Do you have a direct link to the previous version that we can use?
In this case your vendor should be able to provide you the software. Your organization administrator also has access to this software who can distribute it.