Local WMS as basemap

[MandanaMoshref]

I would like to have multi basemap. However, adding a wms doesn't work as it only supports wms version 1.1.1. It seems in the code that if I do not define the version by default it is 1.3. So how in the json file I should indicate the version.
This is at the moment my configuration which doesn't load the wms due to the lack of version support from the wms:
(source: https://geodatenonline.bayern.de/geodatenonline/seiten/wms_dop80cm;jsessionid=EA8846B3A6D4D0418DB558049EB56F8F)
{ "title": "BY WMS", "type" : "wms", "url" : "https://geoservices.bayern.de/wms/v2/ogc_dop80_oa.cgi?", "version" : "1.1.1", "layer" : "by_dop80c", "srs" : "EPSG:4326", "extent" : [-180,-90,180,90] }

In addition, I would like to have mapbox as another basemap. How the configuration should look like? I thought it is there as it is the default basemap for my ckanext-spatial.