Krafton released PUBG patch 10.3 on live servers, bringing visual improvements to Karakin and new sounds for certain weapons that are still optional.
Patch 10.3 brought remastered sounds for four weapons in PUBG but if you prefer to keep the old sounds, you can do so. The four weapons in question are M249, M416, Kar98k and SKS. You can switch between the new and old sounds in the Audio menu.
The weapon sounds are not the only things getting remasters since Karakin is getting a few improvements as well. Lighting has been improved all over the map and will provide a different feel for each area. Besides lighting, there have been a few bug fixes across the map that should result in a more polished experience for everyone.
Reputation system has also been improved so a player's rep doesn't go down when they leave a game before boarding the plane in normal matches only.
In the case of ranked matches, you will still lose reputation, even if you leave the area before getting on the plane. There are a few exceptions though, such as the option to leave the match five minutes after the plane has taken off, provided that you were randomly matched with a teammate that left the game beforehand.
Furthermore, you will have the same option if matchmaking sends you in solo while queuing for ranked squads.
You can find the full PUBG 10.3 patch notes on the official website, including the party emotes.