change required ownCloud version to 4.91
change required ownCloud version to 4.91

Xefir/news,IBBoard/news,IBBoard/news,itstar4tech/news,David-Development/news,David-Development/news,IBBoard/news,itstar4tech/news,owncloud/news,Xefir/news,itstar4tech/news,itstar4tech/news,IBBoard/news,Xefir/news,owncloud/news,owncloud/news,Xefir/news,David-Development/news,David-Development/news