Download iOS 13.3.1 (17D50) for iPhone X (GSM)

You will have to note that you can only restore signed IPSW firmware files using iTunes or 3utools.

Firmware Identifier	iPhone10,6
iOS Version	13.3.1
Release Date	2020-01-28
Update Date	2024-06-03
Sha1sum	a03289af3f0a7a360226fa8cfb47ecea4dd92f9f
Sha256sum	15663dc6ac40748bca8796bb8d10a4047dff18203b4b4cd8ea0bcc9c08e0d35c
md5sum	57172c4ab6b814ea3445bcda5d8cbd2c
Size	3.89 GB
FileName	iPhone10,3,iPhone10,6_13.3.1_17D50_Restore.ipsw
Status

It should be noted that these are the official release notes for the from Apple

iOS 13.3.1 includes bug fixes and improvements. This update:

Fixes an issue in Communication Limits that could allow a contact to be added without entering the Screen Time passcode
Adds a setting to control the use of location services by the U1 Ultra Wideband chip
Addresses an issue that could cause a momentary delay before editing a Deep Fusion photo taken on iPhone 11 or iPhone 11 Pro
Resolves an issue with Mail that could cause remote images to load even when the “Load Remote Images” setting is disabled
Fixes an issue that could cause multiple undo dialogs to appear in Mail
Addresses an issue where FaceTime could use the rear facing ultra-wide camera instead of the wide camera
Resolves an issue where push notifications could fail to be delivered over Wi-Fi
Addresses a CarPlay issue that could cause distorted sound when making phone calls in certain vehicles
Introduces support for Indian English Siri voices for HomePod

For information on the security content of Apple software updates, please visit this website: