CoreNFC does NOT support Mifare Classic 1K, so we've created the Mifare Classic Tools for iOS - MTools Lite app, which can use an external BLE Reader to read/write Mifare Classic 1K card. It also supports reading or writing NFC tag and transportation card which has SAK under 20 and 28. Checkout MTools Lite on App Store

Same happened to me. Still previous icon on multitasking icon even after uninstallation and installation again.