Migrating from Webstore - KC3Kai/KC3Kai GitHub Wiki

As part of Google's manifest V2 phase-out, Google has begun to disable manifest V2 extensions permanently with Chrome v133, which has started being rolled out at the end of February 2025.

What does this mean?

KC3改 will no longer work on mainline Chrome going forward. Furthermore, pushing updates to KC3改 via the webstore will also no longer be possible, and the ability to install KC3改 from the webstore has already been removed in v133.

What will happen to KC3改?

KC3改 will continue being developed and maintained as usual. However, in order to continue using KC3改, you must switch to an alternate method listed below.

Once KC3改 becomes permanently disabled, you will no longer be able to make a Data Backup from Strategy Room. Please do so ASAP before your browser updates if you intend to transfer your data. If you already missed it, see Option 3 for a way to recover it.

Option 1: damecon-browser

damecon-browser, a standalone KC3改 browser, is under development, and a beta build is available for use.

Download here (Expand the Assets section, select damecon-browser-*.Setup.exe)

Please see instructions on its front page.

Recommended for most users. Note however that the current version is still alpha: core features work (including KCCP support and Data Backup restoring), but some side panel and Strategy Room features (such as screen fit) may not work and some browser QOL features may be missing. (currently known missing features)

Option 2: Old Chromium

Install KC3改 in an old version of Chromium which still supports V2 extensions, and use that old version for nothing but playing KanColle.

Recommended for users who wish to keep all features of webstore KC3改 until damecon-browser catches up in development, and do not mind either installing Python or updating KC3改 manually.

Note: For security reasons, not recommended to use old versions of Chromium for anything other than playing KanColle.

Automatic Installation + Update (Windows only)

  • Install Python if it is not already installed.
  • Download chromium-standalone-updater. The updater will download Chromium version 123 and the latest KC3改 release, which is ~450MB of files, so make sure it is in a location with enough disk space, then run start-chrome-win (do not run chrome.exe directly).
  • On subsequent runs of start-chrome-win, it will check for KC3改 updates and automatically download them if available.

Manual Setup

  • Download a version of Chromium which supports V2 extensions (versions before 124 recommended): Official Site/Instructions, Unofficial Listing
  • Follow "Setup development build" guide to choose a way to download KC3改 and install it into Chromium.
  • Note: Unlike with webstore or damecon-browser or the above Automatic Installation, KC3改 updates are not automatic, and must be done manually by downloading the new zip release and overwriting the loaded files, or git pulling.

Option 3: Edit registry flag (temporary solution)

Edit registry flag to extend V2 support in mainline Chrome temporarily until around June 2025.

Recommended only if you did not make a Data Backup before your webstore KC3改 became permanently disabled and wish to recover it, consider this method your last chance to make one.

Note that improperly editing the registry may cause system instability, please do so at your own risk.