Activation servers for older products have been shut down, often causing perpetual licenses to revert to a "30-day trial" or show "invalid serial number" errors.

Due to the security risks, the best course of action is to move to a supported version (Acrobat DC) or use alternatives like Foxit or PDF Xchange.

Note: You may still find perpetual, physical copies for sale on secondary markets like eBay . To provide the best advice, could you tell me:

Because it hasn't been patched since 2017, using XI Pro is highly insecure.

Knowing this will help me provide the exact solution you need. ACROBAT XI PRO SHUTTING DOWN - Adobe Community

Wacom

Adobe-acrobat-xi-pro -

Activation servers for older products have been shut down, often causing perpetual licenses to revert to a "30-day trial" or show "invalid serial number" errors.

Due to the security risks, the best course of action is to move to a supported version (Acrobat DC) or use alternatives like Foxit or PDF Xchange. adobe-acrobat-xi-pro

Note: You may still find perpetual, physical copies for sale on secondary markets like eBay . To provide the best advice, could you tell me: Activation servers for older products have been shut

Because it hasn't been patched since 2017, using XI Pro is highly insecure. adobe-acrobat-xi-pro

Knowing this will help me provide the exact solution you need. ACROBAT XI PRO SHUTTING DOWN - Adobe Community