Shimano 105 compatible 13- or 14- cassettes
Modern rear derailleurs do in fact have a min and max smallest sprocket specification as well as largest min and max largest sprocket specification. You can find the specs here.

The min and max size of the sprockets is not just affected by the chain slack the derailleur can take up, it's affected by the angle of the line the cage moves along relative to the center plane of the bike to maintain separation from the cassette. This is different for short and long cage versions of derailleurs - a long cage derailleur moves at a different angle than a short cage to track a wider range cassette.

The current RD-7000 SS (short cage) and GS (long cage) min and max sprocket specs are:

                 SS    GS 
Low        Max   30T   34T
sprocket   Min   25T   30T
Top        Max   14T   12T
sprocket   Min   11T   11T


So if you have a short cage version you can use a 14 tooth smallest sprocket.