Dont hava “Update” field for licence

Hello,
This post is related to the Sales Countdown Timer. On one of my websites, knjizaraodisej.rs, I have an active Countdown Timer, and I am satisfied with how it works. Now, I would like to purchase a license for my other website, veselaknjiga.com, but when I installed the plugin, there is no “Update” field where I could enter the license. The image is attached. Thank you in advance for your response.