Key developments on August 4: * 5 Russian fighter jets hit by Ukraine's SBU with drones in occupied Crimea, one destroyed * 'Massive' Ukrainian drone strike targets Russian railway station in Volgograd Oblast, local official claims * Ukrainian strike destroys Russian S-300 in occupied Zaporizhzhia Oblast, General Staff says * Ukrainian lawmaker, ex-governor jailed in drone procurement corruption case * Netherlands to deliver $579 million in US weapon systems to Ukraine, including Patriot m