Fire TV devices have a setting called “Developer Options” that lets you install third-party apps from unknown sources. But because Amazon hid the Developer Options on some FireStick TV devices, users can’t let apps from unknown sources install third-party APK files.
Please note that the Developer Options still show up on most of my FireStick and Fire TV devices. Those that have been updated to version 126.96.36.199 are included.
This guide will show you how to add Developer Options to your FireStick if you don’t already have them.
Select FireStick Settings and choose My Fire TV.
Click About if you do not see Developer Options.
Click on your Fire TV Stick quickly 7 times.
You will see a notification at the bottom saying No need, you are already a developer.
Press the back button once and you will now see Developer Options.
You can now go into Developer Options and enable Apps from Unknown Sources.
After the Fire TV OS update 188.8.131.52 went out, Developer Options were taken away from some devices. But if you follow the steps above, you can easily get it back and keep installing your favorite streaming apps.