tmr.alarm not working on ESP12E 0.9.5 firmware

Tested that this sample was not working on dev board:

if not tmr.alarm(0, 5000, tmr.ALARM_SINGLE, function() print("hey there") end) then print("whoopsie") end

Checked firmware version (connected to ESPlorer and pressed reset):
ESP12E default NodeMCU 0.9.5 build 20150318  powered by Lua 5.1.4

Decided to update firmware. Found here that only 9.6 is available precompiled, later ones have to be costum built. Downloaded 9.6 files and uploaded them using ESP8266Flasher.exe

Checked firmware version then:
NodeMCU 0.9.6 build 20150704  powered by Lua 5.1.4

And tested this code sample:

if not tmr.alarm(0, 5000, tmr.ALARM_SINGLE, function() print("hey there") end) then print("whoopsie") end

It worked.