Comment # 7 on bug 1095451 from Ralf Czekalla

Created attachment 823775 [details]
Selective screenshot of Solaar with newest Logitech device I have showing
battery status

This is a screenshot of Solaar with my newest Logitech device I have at hand, a
K400plus.

I haven't seen any problems with Logitech devices over the last years with
Solaar. Only the really old receivers with PS2 connectors are not recognized
because the kernel is not yet extended for these old ones.  

Not sure if the ltunify might cause your problems offering somehow similar
options but AFAIK has not such a nice KDE5/plasma interface as shown in the
screenshots Solaar can offer.