Via [url=https://store.steampowered.com/news/274747/]the Steam store[/url] and [url=https://list.valvesoftware.com/]HLDS[/url]:

[quote=Valve][b][u]Summer 2026![/u][/b]
- Featuring 6 new community maps: Dryfield, Camp Saxton, Shorelight, Redwood, Premuda, and Mojave

- Added the Summer 2026 Cosmetic Case
- Contains 24 new community-contributed items
- Has a chance to give a taunt Unusualifier as a bonus item

- Added 4 new community-contributed taunts to the Mann Co. Store
- Taunt: The Circuit Breaker
- Taunt: Buffoon's Bivouac
- Taunt: Faux-calization
- Taunt: Friendly Fire

- Added 12 new community-created Unusual effects
- 7 new effects for Unusual hats
- 5 new effects for Unusual taunts

- Added the Summer 2026 War Paint Case
- Contains 10 new community-created War Paints that make-up the Summer 2026 Collection
- Has a chance to give a taunt Unusualifier as a bonus item

- All cosmetic and taunt cases will grant Summer 2026 Unusual effects instead of their normal Unusual effects during the Summer event. This does not include crates.
- The Summer event runs through September 15th, 2026

[b][u]General[/u][/b]
- Security and stability improvements
- Fixed bad alpha channel for The Creature's Grin, Rocket Operator, The Bountiful Bow, The Alternative Medicine Mann, and The Candyman's Cap (community fix from Chickenman456)
- Fixed the "Neo Tokyo" warpaint on the BLU team not matching the RED team because the alpha channel was incorrect (community fix from Whurrhurr)
- Fixed bad alpha channel for the Pile of End of the Line Key Gifts' backpack icon (community fix from JoriKos)
- Fixed Stat Clock model attaching incorrectly on dropped weapons (community fix from rabscootle)
- Fixed Stat Clock values always displaying '0' on world models (community fix from rabscootle)
- Fixed intel carrier glow disappearing when Spy cloaks (community fix from shockpast)
- Fixed bad alpha channel for Voodoo Juju's backpack icon (community fix from DiskIntegrity)
- Fixed Silver Botkiller Mk.I having cubemapping in the wrong area due to a VMT error (community fix from Whurrhurr)
- Fixed misspelling on cp_well's BLU rocket clamp texture (community fix from DiskIntegrity)
- Fixed wrong paths in soundscript events for some taunts (community fix from robbilookatme)
- Fixed Spy control point response rules lines playing when disguised/invisible (community fix from Churkinator)

- Fixed weapon Unusual effects (community fix from Cipherlock and rune)
- Fixed particles being orphaned after death
- Fixed the Energy Orb Unusual effect desyncing from the weapon when the player moves too sharply

- Fixed effects flooding the screen when spectating a dead teammate in first person with an unusual weapon (community fix from RGBACatlord)
- Fixed missing coin effect for HOUWAR's second style (community fix from DiskIntegrity)
- Fixed outdated description for the Splendid Screen (community fix from JoriKos)
- Trimmed delay at the start of the sound file for the Panic Attack's shooting sound
- Fixed the Engineer not being able to move for a few seconds after using Taunt: Cheers!
- Updated cp_powerhouse to fix collision problem with crates on final control points

- Updated cp_fortezza
- Reworked interior of shack building next to Point A
- Rebalanced ammo packs around Point A
- Improved visuals across the map
- Made rotation for shortcut path shorter

- Updated koth_blowout
- Prevent sentry guns from being built inside a prop under the stairs in the maintenance room
- Visual changes to improve clarity and consistency[/quote]

Rumor has it:

- Size is close to 500 MB - data capped users should be aware