The smart, safe path is to either purchase a legitimate license (possibly downgrading from a newer version) or switch to a modern, free backup tool. Your data is worth more than a few dollars saved on a pirated key.
Acronis True Image 2017 (now part of the Acronis Cyber Protect Acronis True Image 2017 Activation Key
Search for keywords like "Acronis purchase," "Acronis registration," or "Cleverbridge" (the primary billing provider for Acronis). The smart, safe path is to either purchase