I’ve got a simple ESP8266 app that’s been running for a year and a half without any problems. Starting sometime in the last couple of weeks I keep getting frequent disconnects. It seems to reconnect with no problems. Nothing in my network, WIFI, or Code has changed. Any ideas?
Yes… make some changes 
The rest of Blynk has been progressing regularly since then… including the App, which you have probably updated at some recent time… and which requires you to keep up with the current Blynk Library (and reflashing your code with new library) and Local Server update (if you use it).