@sultan1966 

We do not provide change logs, but that does not mean what you were told is inaccurate. Usually, a post like this that provides incorrect information would be removed. However, in this case, we are responding to ensure there is no confusion. 

Within the hardware version, the ending number is an indicator of which factory the product was manufactured in.  For example, a V2.0 is manufactured in one location, but a version 2.6 is manufactured in another. The actual hardware is the same; the only difference between a V2.0 and a V2.6 is where it's made.  This also alplies to 3-digit hardware versions a V2.20 and a V2.26 are the same.  So when you download a driver for a V2.6, the driver may be named as a V2.0, but it is safe to download and install.  

  @sultan1966  

As far as I am aware, the Extender does not have automatic updates.  When it is connected to a TP-Link ID it has online and offiline updates available.  It may notify you when you log in that an update is available but it does not process an update until you designate to do so.