The of the FileZilla Client that officially runs on Windows XP is in the 3.9.0.1 range. Subsequent updates have shifted support to Windows 7 and newer versions.

This is the most recent version functional on XP SP3.

For those looking to host a server on XP, this version is the presumed final compatible release. Where to Download Safely

It is critical to obtain legacy software from reputable repositories, as unofficial versions may contain malware or unauthorized modifications. Loder Version for Windows XP - FileZilla Forums

While modern versions of the FileZilla FTP client no longer support legacy operating systems, users can still find compatible legacy versions to facilitate file transfers on Windows XP. Recommended Version for Windows XP