FileTransfer 
FileTransfer PRO
Cannot receive files.
When transferring files by Wi-Fi, make sure that the transmission and receiving sides are connected to the same Wi-Fi network.
For Bluetooth file transfers, check that the Bluetooth settings are turned ON for the transmission and receiving sides.
"FileTransfer" Version [1.3.0] or later and "FileTransfer PRO" cannot communicate with earlier versions of "FileTransfer". To enable communications, ensure that both the receiving and sending applications are "FileTransfer" Version [1.3.0] or later, or "FileTransfer PRO".
You can check the version using the "Settings" button.
For Bluetooth file transfers, check that the Bluetooth settings are turned ON for the transmission and receiving sides.
"FileTransfer" Version [1.3.0] or later and "FileTransfer PRO" cannot communicate with earlier versions of "FileTransfer". To enable communications, ensure that both the receiving and sending applications are "FileTransfer" Version [1.3.0] or later, or "FileTransfer PRO".
You can check the version using the "Settings" button.
* If the "FileTransfer" version is earlier than [1.1.0], the "Settings" button does not appear.
FileTransfer
I can't extract ZIP.
Only "FileTransfer PRO" can compress files into zip or extract zip files.
FileTransfer FileTransfer PRO
Can I get PC data into this app?
If you have installed iTunes on PC, you can get data via iTunes.
"FileTransfer PRO" can let you download / upload files via PC browser when PC and iPad/iPhone are on a same Wi-Fi. You also can delete files / folders or create folders.
"FileTransfer PRO" can let you download / upload files via PC browser when PC and iPad/iPhone are on a same Wi-Fi. You also can delete files / folders or create folders.
FileTransfer PROI set up activation lock and forgot the password.
If you forgot the password, the only way to unlock is to delete app.