We've solved things by our selves to get tDataset from Version10.x working under XE8. The only thing which has to be changed is following code in adsdata.pas:
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function TAdsDataSet.BuildFilterString( poFields : TList;
bExactCompare : Boolean;
bCaseInsensitive : Boolean ) : string;
and change it to:
function TAdsDataSet.BuildFilterString( poFields : TList<TField>;
bExactCompare : Boolean;
bCaseInsensitive : Boolean ) : string;
Hope this helps others ...