This OTA for HTC One A9 was pushed for the unlocked edition and version of this OTA is 1.57.617.41. This is for the US unlocked edition and if you wish to install this update on your HTC android phone, you will have to S-OFF your device, change CID and MID using fastboot command from download mode. Here are the commands:
fastboot oem writecid 11111111
fastboot oem writemid 2PQ912000
Then you will be able to flash US firmware and this OTA bearing version 1.57.617.41. Go into recovery mode and flash this OTA update. Keep in mind that you have to be on stock, untouched ROM in order to flash this OTA update. If you have rooted HTC One A9, flashing this OTA will fail.