Destiny 2.4.0's full patch notes have already been published by Bungie. This covers the changes in the weapon balance and other promising features. In line with Destiny: Rise of Iron, Bungie has made known to the public the changes that are coming into the game - most of which are related to weapon balance. Bungie released in a statement that every new expansion that they do considers weapon balance changes, and they applied this to the Rise of Iron too.
According to Gamespot, Bungie was quoted to have said that they have already learned from each of their success and mistakes. They have also learned to further analyze every player activity from their wide reserves of players. Due to these reasons, they came out with a plan to execute all of their plans. The expansion will certainly modify the balance landscape through improving old and devising new weapons, so that it could keep up with the missing roles while fulfilling what the players would want to happen.
Based upon what the developers have figured out, the new update 2.4.0 was born. This update will include major changes to a great number of Destiny's weapons; it also includes Exotics. The base range of the Fabian Strategy has increased its base range and stability. Additionally, the Thorn's base range will be lessened by 25 percent. Bungie has also made changes in reducing the damage for sniper rifle, therefore mid-high snipers will not be able to kill high-armor player especially during super activation. However, No Land Beyond, which is a mid-high impact sniper, remains the same despite the changes. This is maybe because it serves as a primary weapon while the others are just secondary.
According to VG247, full patch notes made for the 2.4.0 will be published at an unpredictable date yet, since there is yet no revelation about it yet. On the other hand, Rise of Iron will be released on September 20 on PlayStation 4 and Xbox One. Check the full patch note here.