v2.6 had no elevation related fixes listed that were listed:

Changes made from version 2.50 to 2.60:
- Fixed occasional issue with Edge shutting down when scrolling through Saved Rides.
- Fixed occasional issue with Edge shutting down when Mode button was pressed while following a Course.
- Fixed issue where user could not change vertical zoom scale for a Course profile.
- Fixed a problem where indoor rides in History could slow down access to Where To? menu.
- Fixed issue with Advanced Workouts not showing up under Today when the workout is scheduled for the current day.
- Fixed issue where sometimes the most recent History would not be written out to XML until disconnecting and reconnecting USB.
- Corrected the Average Power value shown for Entire Ride in History.
- Removed filtering from power data stored in History files.
- Made some corrections to the Polish and Portuguese languages.


v2.5 is where there were some however:

Changes made from version 2.40 to 2.50:
- Implemented change to allow the user to access Map Setup option for tracks which will allow showing that track on a map, and what color to display it in.
- Added ability to set Off-Route Recalculation behavior in Routing menu. User can set it to Automatic, Off, or Prompted.
- Fixed issue with long routes shutting down.
- Fixed issue where Autopause and Start/Stop were not getting saved into the History files. This could also cause Courses created from this History to not register these times.
- Fixed issue where History files would occasionally not upload due to misaligned data.
- Fixed inaccurate elevation when moving to and from areas with distinctly different altitudes or atmospheric pressures.
- Fixed random elevation spike in the first few track points.
- Added the ability to delete tracks.
- Fixed issue where speed would drop to 0 going through turns.
- Fixed issue where viewing a Course on a map went to the wrong location.
- Fixed barometer initialization issues in situations where the unit is turned off and back on within 5 minutes in the same location.
- Fixed issue with Course List where actions could be applied to the wrong Course.
- Fixed issue where course guidance lines were drawn on top of roads.
- Fixed issue with repeated Autopausing when using a wheel sensor.
- Fixed issue with creating a Workout with Spanish language selected.
- Improved German translations.

The Edge uses a barometer to measure elevation. Thus it is subject to changes in barometric pressure. It has to be able to determine if a change in pressure is due to the unit changing elevation or pressure changing due to weather.

If you are on a long ride that starts and stops at the same location and the presseure changes a lot during that ride there is a very good chance the unit will not show the same start stop elevation. The complaint that many of us Edge users have is that there is no way for the user to tell the unit what the correct pressure and or elevation is. If we could do that then a lot of the issues would be resolved.

Sorry, you asked a simple question but I gave you got this!