Hello,
Thank you for your post.
Unfortunately, there are no free upgrades to Parallels Desktop 26.
If you require Parallels Desktop 26 license, please check our website: https://www.parallels.com/products/desktop/buy/#upgrade
If you already own a Parallels Desktop 18 permanent license, you can purchase a Parallels Desktop Permanent Upgrade license (One-time Purchase option) which is at a lower price than a full license.
Regards,
Parallels Team
