Android huendeshwa kwenye anuwai kubwa ya vifaa na matoleo ya OS ("fragmentation"), kwa hivyo programu lazima zishughulikie uoanifu wa toleo (version compatibility) — kusaidia matoleo ya zamani huku zikitumia vipengele vipya kwa usalama. Kuelewa SDK levels, compatibility libraries, na graceful degradation ni muhimu.
SDK levels: min, target, compile
minSdk → the OLDEST Android version the app supports (older devices can't install it)
→ lower minSdk = more devices reached, but more compatibility work
targetSdk → the version the app is TESTED/optimized against (and opts into its behaviors)
→ should be kept current (Play requires a recent targetSdk)
compileSdk → the SDK version used to COMPILE (access to newer APIs)
→ Balance: support enough old devices (minSdk) while targeting current behavior (targetSdk).
