Via [url=https://store.steampowered.com/news/85643/]the Steam store[/url] and [url=https://list.valvesoftware.com/]HLDS[/url]:

[quote=Valve]- Added the Summer 2021 Cosmetic Case
- Contains 18 new community-contributed items
- Adds 6 new community-created Unusual effects
- Numerous security and stability improvements
- Added a cooldown before a player can create a vote when they join a match already in-progress
- sv_vote_late_join_time controls the grace period after the match starts before the cooldown is applied: default 90 secs
- sv_vote_late_join_cooldown controls the length of the cooldown: default 5 min
- Kick votes will end early and automatically pass if the vote target leaves the match during the vote
- Added a ConVar to control players changing their name during a match
- tf_allow_player_name_change: default is 1
- Matchmaking servers will set this to 0
- Updated the player list in the vote-kick dialog to show the time each player has been connected to the server
- Removed the disconnect reason from the message when players leave the server
- Updated the Mann vs. Machine "inspect" command to only work for players in your party or in your Friends list
- Moved materials for the community particle effects into the Effects/workshop sub-folder to distinguish them from Valve materials
- Updated/Added some tournament medals
- Updated the localization files
- Updated cp_snakewater_final1
- Fixed clipping throughout map
- Fixed explosion splash being caught by objects throughout map
- Made movement smoother throughout map
- Reworked some problematic areas like the kitchen
- Minor visual enhancements throughout the map
- Updated cp_process
- Fixed incorrect skin for the Red radio tower[/quote]

Rumor has it:

- /u/Serird has put together [url=https://www.reddit.com/r/tf2/comments/o5rxqp/tf2_update_for_62221/h2ocqdf/]a listing of the contents of the Summer 2021 Cosmetic Case[/url] (and Unusual effects), complete with Steam Workshop links to pass some applause on to item/effect creators that made it in the case

- Community server operators have noticed that a 64 MB cap on custom downloadable content has been implemented, including to maps served through FastDL. While it's possible this may be part of the "numerous security and stability improvements", it appears that it may not be entirely intentional as Eric Smith has sent a follow-up message to the HLDS list stating that Valve is "looking into the reports" of clients being unable to download larger maps
- This has been fixed [url=https://www.teamfortress.tv/post/1040115/tf2-update-for-6-22-21]in update #2[/url]

- Because there are now multiple ways you could be prevented from calling a vote to kick, [url=https://github.com/SteamDatabase/GameTracking-TF2/commit/bed9cec893df4fa828a12231b7bd4a45d558a765#diff-9bd2d6650be24fd55c0f4e2e605ccef54ed9999291ff2ed326a0dd7842796647L868]strings will no longer be specific as to the cause[/url] (previously, it would've been only for having called another vote recently)

- The new cluster has been up for a couple of months already, but seeing as [url=https://github.com/SteamDatabase/GameTracking-TF2/commit/bed9cec893df4fa828a12231b7bd4a45d558a765#diff-01ba957b0f0d55d164301650591ac7b823c999924daeb46879eaef57f9646731R17256]it only just now got its string[/url] it's worth mentioning anyway: the EU West server cluster (as it's known in Dota 2 and CS:GO) [url=https://github.com/SteamDatabase/SteamTracking/commit/51dbbf634b00955d5313b6fd1c24d7574a7bb219]has been relocated[/url] from Luxembourg to Frankfurt, Germany

- For a complete listing of today's tournament medal additions and updates, please click on https://www.teamfortress.tv/post/1040146/tf2-update-for-6-22-21 due to character limit reasons

- This update's arrival brings an end to another record-shattering drought that lasted just a few days short of 4 months, or more specifically, 112 days without an update, with the last one having occurred on 3/2/21
- This update is just the 3rd to happen so far in 2021, which itself is almost halfway done. By this point of the year last year, the game had 5 updates by the same day of the 2020 calendar year (which became 6 a couple of days later on 6/24/20)
- The previous all-time record drought was a stretch of 80 days in a similar timeframe last year, from 1/18/20 to 4/7/20 (4/8/20 UTC)
- Before that, the now 3rd all-time longest drought was a stretch of 72 days from 5/14/19 to 7/25/19 (7/26/19 UTC)

- Lots of localization file changes, as well as item schema changes [url=https://github.com/SteamDatabase/GameTracking-TF2/commit/bed9cec893df4fa828a12231b7bd4a45d558a765]can all be viewed here[/url]
- And in case you forgot with it having been so long since the last update, translations are made possible in part by the efforts of [url=https://translation.steampowered.com/]Translators Like You - Thank You[/url]

- Size is ~55 MB