The instructions for floating licenses are buried on the SmartBear website. Try these steps to upgrade to TC 11 with floating license (it worked for us!).
Pre-requisite: Obtain your license key/s by logging into my.smartbear.com
1. Open a web browser on the licensing server. This part is important, you have to do this on the machine that is your licensing server!
2. Navigate to http://localhost:1947
3. Click on 'Sentinel Keys'.
4. Select option on right sight of screen to download 'C2V' file.
5. Click on this link and upload your C2V file: https://my.smartbear.com/manual-license-activation/
6. Download the .v2C file genrated by the site in step 5.
7. Go back to http://localhost:1947 and select 'Update / Attach'.
8. Upload the .v2C file obtained in step 6 to your licensing server.
Repeat above steps for licensing Test Execute if you have licenses for that too.