Can the files come back?
Older Djvu versions used a fixed offline key, and a free tool from Emsisoft supports many such variants.
Variants from August 2019 onward often use a key made for each victim online, and the operators keep that key.
If your note shows a personal ID, upload the note and one encrypted file to ID Ransomware, then run the Emsisoft Stop Djvu decryptor on a copy. It tells you whether your files used an offline key, an online key or one it does not yet know.
We last read about this in November 2026 and found no confirmed free decryptor for the Nbwr variant. The outcome “online ID, decryption impossible” is common for new Djvu names. Keep the encrypted files, because keys are sometimes released later.
The practical routes are clean backups, OneDrive or other cloud version history, File History, Previous Versions, and a partial salvage with a recovery tool such as PhotoRec. Restore only after the PC is clean, and never trust sites that sell a decryptor.