Ladda ner Syncthing 2.1.6

Major changes in 2.1
- Devices and folders can now be grouped in the GUI by setting the new
group attribute.
- HTTP and HTTPS proxies with support for CONNECT can now be used, in
addition to the existing support for SOCKS proxies (the environment
variable all_proxy=https://...).
- Block indexing can be turned off for folders where it's more desirable to
optimise for reduced database size and overhead than minimal transfer
size (the blockIndexing attribute on folder configuration).
- GUI login session duration can be configured to be longer or shorter than
the default one week, or set to infinitely long. The cookie path can also
be adjusted. (The sessionCookieDurationS and sessionCookiePath
attributes in the GUI configuration.)
This release is also available as:
- APT repository: https://apt.syncthing.net/
- Docker image: docker.io/syncthing/syncthing:2.1.6 or ghcr.io/syncthing/syncthing:2.1.6
({docker,ghcr}.io/syncthing/syncthing:2 to follow just the major version)

What's Changed

Fixes
- fix(model): introducers should not be able to add themselves to folders by @calmh in #10880
- fix(gui): add accessible labels to buttons in Edit Device modal (fixes #10873) by @tomasz1986 in #10874
- fix(model): properly error out when a temp file can't be created by @calmh in #10883
- fix: disable keepalive on most outgoing HTTP connections by @calmh in #10891
- fix(monitor): continue log writes when stdout is unavailable on detached Windows consoles (fixes #10882) by @Shablone in #10889
- fix(gui): improve header and button color contrast (fixes #10488) by @giri256 in #10815
- fix: use global short lived HTTP client with proper HTTP/2 support by @calmh in #10901
- fix: remove unnecessary delay in index transmission by @calmh in #10908

Other
- fix(watchaggregator): properly convert floating-point time duration (fixes #10899) by @calmh in #10900

New Contributors
- @giri256 made their first contribution in #10815