Grav 1.3.9 introduced a major bug that causes GPM to stop working in the Admin plugin. However, this has been fixed in version Grav 1.3.10 that is now available in the downloads, via CLI GPM, or Direct Install in the admin plugin. In response to this issue, we're going to start a new official Testing Team so we can get a better handle on these kinds of potential issues in the future (see bottom).

CLI Grav 1.3.9 -> 1.3.10 Fix

For those of you that have already updated to Grav 1.3.9 and can use the CLI, you can use still use GPM to update to 1.3.10 with bin/gpm selfupgrade:

$ bin/gpm selfupgrade -f                                                                          

GPM Releases Configuration: Stable

Grav v1.3.10 is now available [release date: Wed Dec  6 06:44:17 2017].
You are currently using v1.3.9.
Would you like to read the changelog before proceeding? [y|N] n
Would you like to upgrade now? [y|N] y

Preparing to upgrade to v1.3.10..
  |- Downloading upgrade [3.2M]...   100%
  |- Installing upgrade...    ok
  '- Success!

Clearing cache

Cleared:  /webroot/grav/cache/*

Touched: /webroot/grav/user/config/system.yaml

Admin Grav 1.3.9 -> 1.3.10 Fix

For those who rely on the Admin plugin for your updates, you can also update from 1.3.9 to 1.3.10 using the Tools -> Install a zip package from a remote location Utility, simply paste in the URL:

https://getgrav.org/download/core/grav-update/1.3.10

and click the Install button.

Issue Post Mortem

This particular error came about because the code change in question was made to the Grav core to enable better offline support for GPM, and because of this, I only tested in CLI GPM. As things seemed to work as expected when using GPM from the CLI, I just assumed they would also continue to work the same way via the Admin. Unfortunately this was not the case, and in the week that the code sat in develop branch of Grav, I didn't have reason to try any admin-based GPM updates, nor did anyone else report any issues. Because of this it has become clear that we need a dedicated testing team, who can more thoroughly test commits and fixes across a wider range of use cases, as well as platforms.

Official Grav Testing Team

If you are interested in joining this team, let me know on our Grav chatroom and i'll add you to our new private testing-team channel. In that room, we can discuss the best approach to test development version of Grav to ensure maxiumum backwards-compatibility and to reduce potential issues such as this.

I will also be adding the new testing-team to the About Grav page to show appreciation for your efforts.