Error while trying to add plugin

[ariko861]

In the plugin admin section, when I click on "add" to search for new plugin, I get this error :

 Twig \ Error \ RuntimeError
An exception has been thrown during the rendering of a template ("RocketTheme\Toolbox\Blueprints\BlueprintForm::doLoad(): Parameter #1 does not contain array of filenames").

[pseudorandomnumber]

I have the same. The file with the error seems to be: WEBROOT/user/plugins/admin/themes/grav/templates/partials/plugins-list.html.twig

edit:
for a quick fix, I commented out the line 18 in the file so it reads:
{# {% set data = admin.data('plugins/' ~ slug) %} #}

[mahagr]

This has been fixed for the next RC.4

[Kobraz]

I installed today and I have the same problem...

When will RC4 become awailable?

How do I update GravCMS? Do I have to download and install again?

[pd-giz-dave]

For the record this is the fix I used in rc3:

{% if not installing %}
            {% set data = admin.data('plugins/' ~ slug) %}  {#27/01/20 DCN: This goes bang when installing#}
 {% else %}
            {% set data = {enabled: false} %}               {#27/01/20 DCN: Irrelevant when installng#}
 {% endif %}

At lines 18..22 in:

user/plugins/admin/themes/grav/templates/partials/plugins-list.htm.twig

To be clear: this is a fix I applied to RC3 for myself, it is not in RC3 itself.