The biggest hurdle is compatibility. While support for Android 5 and 6 was briefly maintained in legacy builds, Android 4 is effectively unsupported by the modern APT package manager.
Using your device’s old browser (or sideload via USB), download termux-app_v0.83.apk . A trusted mirror is the Termux GitHub Releases page under the "Pre-0.100" tags. termux android 4
: The Termux:Float add-on allows for a persistent terminal window over other apps. The biggest hurdle is compatibility
: For advanced users, Linux Deploy allows you to install a full Linux distribution (like Debian or Ubuntu) inside a chroot environment. This is often the most powerful way to get a modern Linux terminal on KitKat 4.4. A trusted mirror is the Termux GitHub Releases
: Google Play version for Android 4 is no longer available. You must sideload the APK.
The official Termux app is only compatible with Android 5.0 or later
: Historically considered the "go-to" for Android 4.4 and below, providing a Java/C/C++ development environment.