-dit(bf(--delete-after)) By default rsync does file deletions on the
-receiving side before transferring files to try to ensure that there is
-sufficient space on the receiving filesystem. If you want to delete
-after transferring, use the --delete-after switch. Implies --delete.
-
-One reason to use --delete-after is to avoid a delay before the start of
-the transfer (while the receiving side is scanned for deletions) as this
-delay might cause the transfer to timeout.
+Beginning with 2.6.4, rsync does file deletions on the receiving side
+incrementally as each directory is being transferred (which makes the
+transfer more efficient than a separate delete pass before or after the
+transfer). If you are sending files to an older rsync, --delete will
+behave as --delete-before (see below). See also --delete-after.
+
+dit(bf(--delete-before)) Request that the file-deletions on the receving
+side be done prior to starting the transfer, not incrementally as the
+transfer happens. Implies --delete.
+
+One reason to use --delete-before is if the filesystem is tight for space
+and removing extraneous files would help to make the transfer possible.
+However, it does introduce a delay before the start of the transfer (while
+the receiving side is being scanned for deletions) and this delay might
+cause the transfer to timeout.
+
+dit(bf(--delete-after)) Request that the file-deletions on the receving
+side be done after the transfer has completed, not incrementally as the
+transfer happens. Implies --delete.