While Firefox 68 is "old" by modern standards, it is significantly more secure than browsers from 2013-2014 originally bundled with KitKat. Important Safety Tips Avoid Sensitive Tasks:
This version has not received security updates since mid-2020 and contains known vulnerabilities. Certificate Issues: Mozilla Firefox Apk For Android 4.4 2
The last version compatible with KitKat (API level 19) was Firefox 68 (released in 2019). Mozilla ended security updates and support for Firefox 68 in August 2020 . While Firefox 68 is "old" by modern standards,
: The most secure way to obtain the APK is directly from the Mozilla Archive . Mozilla Firefox Apk For Android 4.4 2
Mozilla Firefox for Android 4.4.2: Compatibility and Best Versions For users still operating devices on Android 4.4.2 (KitKat)