Hi - I had ls Version 2.65 on my server inside a folder name "survey". I wanted to replace my intallation as ls2.06lts without changing url so I renamed the folder as surveyold and created new folder with the same name "survey". I then downloaded ls2.06lts as zip from github and installed in this new folder "survey" and everything worked fine for two days. Today when I tried to login ls2.06 I found it is updated to Version 2.65.1+170522. Please suggest how this may happen.

Some more observations:
#I have ls2.06lts(downloaded from github) on two other servers for an year and they never got updateded to 2.6.
#I think ls source code downloaded from github do not update via comfort update.
#Is this something that happened because earlier I had 2.6 inside folder name "survey"(which I renamed to surveyold) and then installed ls2.06lts in a folder with same name as before. Maybe ls comfort update has some sort of links to update ls instalances?

Also please note that several people have admin rights of ls installation. Is it possible that someone has accidentally/intentionally upgraded from 2.06 to 2.6 by clicking somewhere in admin area?

Hi...

just switch in application/config/version.php

github.com/LimeSurvey/LimeSurvey/blob/2....n/config/version.php

I now did this just after finishing the installation and before logging in for the first time. Or should I have I updated it even before initiating installation? Or this doesnt make any difference?

I now see this message in comfort update tag. Hope It won't get update now.

the problem comes from that your users are administrators.
updates are announced on twitter, so just follow us and you'll now when an update is available for 2.06lts branch.
eg:

2.06LTS build 160524 released!