The Arduino community released version 1.6.6 the day before yesterday (2015-11-03).

Could somebody check the compatibility with your code version on your operating system?
If you could, please post the following things:

• operating system (Windows 7,8,10, Linux version, Mac OSX)
• architecture 32bit, 64bit
• Arduino version (stable, staging or the git hash)
• used Arduino package manager or not
• Hardware (ESP8266 Generic, NodeMCU, etc.)???
• the working example sketch
• which works not?

Previously thanks for your posts.

My tests:

• Ubuntu 15.04 x64 and 14.04 x64
• ESP8266-01 generic board + FTDI
• no package manager
• version 2f3f1f5
• ESP8266WebServer/HelloServer example sketch

Travis link for Arduino 1-6-6 try: