We just made a small change to update_entity() (and by extension, reason_update_entity()). You can now pass a last_modified value in the update array, and the last_modified date of the entity will be set to that value. Previously update_entity ignored any last_modified value passed, always setting it to mysql NOW().
This change was made to accommodate a need for a way to update archived entities without changing their last_modified dates -- now one can do this by just including the item's last_modified date in the updates array.
This change will not effect most code, but there is a specific case where things will change -- if your code was taking advantage of the fact that update_entity was ignoring last_modified, and passing a full array of current entity values to the function. Any code that does this will now, in effect, NOT be updating the last_modified time. This could be confusing, particularly in the history/archive module.
As always, best practice for using reason_update_entity() and update_entity() is to pass just those values that have changed. If you have been following this practice, your code should continue to work without modification.