Have given up completely on TeamViewer.
Too frequent "updates" that destroy previously functional product compatibility.
Thank you for your message.
Is it indeed a big dilemma that every IT company has.
We are always torn between:
We are sorry to hear that you encountered compatibility issues with Yosemite.
You will find all the information you need in our Knowledge Base article here: Which operating systems are supported? / macOS
I thank you in advance for your understanding.