Installing Jdownloads 4.1

[Spark640]

Just in case anyone has the same issue when updating from the previous version to 4.1.
On my staging site I went for a straight update but then got an error

    0 Call to undefined method Joomla\Database\Mysqli\MysqliDriver::getErrorNum()

Which means Joomla is still trying to use the old database method, likely some left over files. Fixed by uninstalling Jdownloads (select 'no' when asked about files, images, etc) and then reinstalling 

[Arno]

Thanks for reporting this.
This kind of error usually points to leftover old jDownloads files from an earlier installation or update attempt.

A uninstall/reinstall can work as a workaround, but it is not ideal because existing jDownloads configuration such as component settings, module assignments or plugin settings may be lost.

So the safer recommendation is:
make a backup first, restore the site to a clean pre-update state if needed, and then retry the update with the corrected 4.1.1 package on that clean copy.

We have also hardened the installer code further for the next build.