  We analyze physical characteristics of late-type stars wherein the Kepler
mission registered superflares. We use the revised stellar fundamental
parameters, i.e. effective temperatures Teff and surface gravitational
accelerations log g, from the Kepler archive published in 2017, as compared to
previous studies by Balona (2015) based on the release of 2011. Among
superflare stars there are both single objects and members of eclipsing
binaries. We select the late-type stars (with Teff $< 6500$ K) wherein occured
the most powerful flares with the total flare energy $> 10^{35}$ erg and
consider their locations in the (Teff - log g) diagram. Both components of
binaries and single stars appear to reside mostly in between the main sequence
and the subgiant branches and therefore have larger radii compared to that of
the Sun. Besides, as a rule these single stars are fast rotators and can be
considered as young objects that it is difficult to attribute to "solar-type
stars". Extremely high flare energy of these stars requires quite strong
magnetic fields that cannot be generated even due to scaling of the solar
dynamo. Apparently, for explanation of the strongest non-stationary phenomena
on stars considered, it would be worthwhile to attract another regime of the
dynamo mechanism that can be realized in these objects.
