Looking at a previous discussion from 2017 in these support pages it may be correct that the file is a .bin file.
https://community.sony.co.uk/t5/other-tvs/cannot-update-firmware-on-a-bravia-kdl-37ex503/td-p/228486...
The outcome to the issue was to put the .bin file in folder called
sony_dtv0FA00A00A0A0_00020100
Copy the folder with the .bin file onto a USB formatted as FAT32.
Insert it in the TV and try the update process again.
It is not always recommended to use an update from a third party site unless you are completely confident
of its provenance.
In January of this year Sony removed most of its legacy software for its older products from its download pages, this included your model of TV.
https://www.sony.co.uk/electronics/support/lcd-tvs-legacy-lcd-tv/kdl-32ex717/software/00271214
The last update for your TV was released in January 2015.
If you do manage to install the software you downloaded you may find that the streaming services you wish
to use may still not work on your TV as they may use newer protocols that may not be compatible with the software on your TV. In that case it may be necessary for you to buy a another device such as a PVR or fire stick that can provide you with the services you require.
Or you could buy a new TV.
