Suddenly My SN is Not Valid

[glasowj 0]

Tried to use Nitro Pro today and it said my trial period is expired. I haven't been on trial for months. I been using SN ***, received from you on 10/27/19, but now it's showing as no longer showing as valid.

Edited February 4, 2020 by Leslie V.
Confidential information deleted

[Leslie V. 0]

Hello @glasowj

Thanks for reaching out to us!

Please uninstall the old version of Nitro Pro and install Nitro Pro 13. You can get the correct version 13 installers from this page: 
https://www.gonitro.com/nps/product-details/downloads

After installation, you can activate by opening Nitro, click on the Help tab > About Nitro Pro > Activate and enter your serial.

I hope that helps!
 

[glasowj 0]

I uninstalled Nitro Pro 13.2.6.26 and installed 13.9.1.155. This worked, but the larger question is why did 13.2.6.26 fail to continue showing as activated? Especially given that my other two copies of 13.2.6.26 on different computers continued without any problem. Is it normal for change in version to break activation?