Since Edmund Gettier's 1963 paper, proposed fourth conditions (a no-false-lemmas clause, causal theories, reliabilism, safety and sensitivity conditions, virtue epistemology) have each met their own counterexamples, and no replacement analysis commands consensus.
What would resolve this An analysis of knowledge that survives every known Gettier-style case without ruling out clear cases of ordinary knowledge would resolve it; some epistemologists instead argue the project of analyzing knowledge into more basic conditions should be abandoned.
OpenEpistemologyStanford Encyclopedia of Philosophy