- Pay attention that UTCTime can not hold full year, so all years
- having < 50 years are treated as 20xx, 19xx otherwise, according
- to X.509 recommendation.
+ Only **naive** ``datetime`` objects are supported.
+ Library assumes that all work is done in UTC.
+
+ .. warning::
+
+ Pay attention that ``UTCTime`` can not hold full year, so all years
+ having < 50 years are treated as 20xx, 19xx otherwise, according to
+ X.509 recommendation. Use ``GeneralizedTime`` instead for
+ removing ambiguity.