Please look at the example below. Superscripts are almost completely overlapped to the last letter. Version 1.2020.8 was ok, but versions 9 and 10 are not.
@startumlskinparam { dpi 300}
:eMail PDF to customer<sup>2</sup>;:Print PDF in BW<sup>3</sup>;@enduml
http://www.plantuml.com/plantuml/png/SoWkIImgAStDuIhEpimhI2nAp5Mevb9GK4Wfo5GmDZ3WgkNYiahrJSpCKGXmSLCeoLT8BYqkoSzDBR8fBYsmCxBH1r7MN5O1HPbv9M0rcNaAJk5WMMEOB9T3QbuAq180
(--------)