First, click the jigsaw button in the top right corner of the screen;

There, click "Manage Extensions":

In the window that opens, toggle the "Developer Mode" in the top right corner:

Now, click the "Update" button in the top-left area of the screen and wait a little:

If you have been directed to this page by a support team, they will tell you which version to expect. You can find it here:

In this example, the version is "1.7.12".