Hi everyone,
Unfortunately, a number of users have reported a problem with the Upgrade from phpList 3.4.0 to 3.4.1, whereby at the “Updater is Loading” step, “Next” isn’t functional any more, and you cannot continue.
This was due to an unintentionally introduced PHP 5.6 dependency that affects any installation using an older version of PHP. You can verify that you have this problem by enabling error reporting on your web server and looking for the following PHP syntax error on your logs:
Parse error: syntax error, unexpected '.', expecting ',' or ';' in [...][...] on line 19
Fix
To fix this issue please replace the index.php file within /lists/updater/ with this version of the file downloadable from GitHub.
A fix for this issue will likely be included in the next release so all installations running on PHP 5.3 can continue to use the Automatic Updater for the time being. Generally you should update from PHP 5.3 as soon as possible as support will be dropped in future.
Fast community feedback has been very helpful in identifying this issue and producing a fix for other people – thanks!