With at least Eclipse 4.17 the class org.eclipse.jface.util.Assert (which was set to deprecated a few versions earlier) is gone.
Therefore the current Subclipse version is not compatible to Eclipse 4.17.
It should be replaced by org.eclipse.core.runtime.Assert. One occurence is the diff view in the revert dialog (org.tigris.subversion.subclipse.ui.dialogs.CompareDialog).