diff --git a/ush/bash_utils/check_for_preexist_dir_file.sh b/ush/bash_utils/check_for_preexist_dir_file.sh
index 7b9b59772..61d6a494a 100644
--- a/ush/bash_utils/check_for_preexist_dir_file.sh
+++ b/ush/bash_utils/check_for_preexist_dir_file.sh
@@ -63,7 +63,7 @@ where the arguments are defined as follows:
 
   method:
   String specifying the action to take if a preexisting version of 
-  dir_or_file is found.  Valid values are \"delete\", \"rename\", and \"quit\".
+  dir_or_file is found.  Valid values are \"delete\", \"upgrade\", \"rename\", and \"quit\".
 "
 
   fi
@@ -84,7 +84,7 @@ where the arguments are defined as follows:
 #
 #-----------------------------------------------------------------------
 #
-  local valid_vals_method=( "delete" "rename" "quit" )
+  local valid_vals_method=( "delete" "upgrade" "rename" "quit" )
   check_var_valid_value "method" "valid_vals_method"
 #
 #-----------------------------------------------------------------------
@@ -112,6 +112,46 @@ where the arguments are defined as follows:
 #
 #-----------------------------------------------------------------------
 #
+# If method is set to "upgrade", 
+#  keep preexisting directory intact except that
+#  when preexisting directory is $EXPDIR, do the following:
+#    save all old files to a subdirecotry oldxxx/ and then
+#    populate new files into the $EXPDIR directory
+# This is useful to keep ongoing runs uninterrupted:
+#  rocotoco *db files and previous cycles will stay and hence
+#    1. no need to manually cp/mv *db files and previous cycles back
+#    2. no need to manually restart related rocoto tasks failed during
+#         the workflow generation process
+# This may best suit for incremental system upgrades.
+#
+# Alternatively, one can always elect to use the "rename" option 
+#   and then manually do the above aftermath
+#
+#-----------------------------------------------------------------------
+#
+    "upgrade")
+       if [[ "${dir_or_file}" == "${EXPTDIR}" ]]; then
+         local i=1
+         local old_indx=$( printf "%03d" "$i" )
+         local old_dir_or_file="${dir_or_file}/old${old_indx}"
+         while [ -d "${old_dir_or_file}" ]; do
+           i=$[$i+1]
+           old_indx=$( printf "%03d" "$i" )
+           old_dir_or_file="${dir_or_file}/old${old_indx}"
+         done
+
+         print_info_msg "$VERBOSE" "
+   Specified directory or file (dir_or_file) already exists:
+     dir_or_file = \"${dir_or_file}\"
+   Moving (renaming) preexisting directory or file to:
+     old_dir_or_file = \"${old_dir_or_file}\""
+
+        rsync_vrfy -a --exclude "old*" "${dir_or_file}/" "${old_dir_or_file}"
+       fi
+       ;;
+#
+#-----------------------------------------------------------------------
+#
 # If method is set to "rename", we move (rename) the preexisting directory
 # or file.
 #
diff --git a/ush/bash_utils/filesys_cmds_vrfy.sh b/ush/bash_utils/filesys_cmds_vrfy.sh
index d11ec4720..e5d856372 100644
--- a/ush/bash_utils/filesys_cmds_vrfy.sh
+++ b/ush/bash_utils/filesys_cmds_vrfy.sh
@@ -234,6 +234,12 @@ function cp_vrfy() {
   { restore_shell_opts; } > /dev/null 2>&1
 }
 
+function rsync_vrfy() {
+   { save_shell_opts; set -u +x; } > /dev/null 2>&1
+   filesys_cmd_vrfy "rsync" "$@"
+   { restore_shell_opts; } > /dev/null 2>&1
+ }
+
 function mv_vrfy() {
   { save_shell_opts; set -u +x; } > /dev/null 2>&1
   filesys_cmd_vrfy "mv" "$@"
diff --git a/ush/config.sh.RRFS_ens b/ush/config.sh.RRFS_ens
index bb34be263..defe3f66e 100644
--- a/ush/config.sh.RRFS_ens
+++ b/ush/config.sh.RRFS_ens
@@ -15,7 +15,7 @@ VERBOSE="TRUE"
 RUN_REALTIME=TRUE
 
 RUN_ENVIR="nco"
-PREEXISTING_DIR_METHOD="rename"
+PREEXISTING_DIR_METHOD="upgrade"
 
 PREDEF_GRID_NAME=RRFS_CONUS_3km
 ADDNL_OUTPUT_GRIDS=( "clue" "hrrr" )
diff --git a/ush/config_defaults.sh b/ush/config_defaults.sh
index 715933b32..305f798b2 100644
--- a/ush/config_defaults.sh
+++ b/ush/config_defaults.sh
@@ -978,13 +978,17 @@ PREDEF_GRID_NAME=""
 # use to deal with preexisting directories [e.g ones generated by previous
 # calls to the experiment generation script using the same experiment name
 # (EXPT_SUBDIR) as the current experiment].  This variable must be set to
-# one of "delete", "rename", and "quit".  The resulting behavior for each
+# one of "delete", "upgrade", "rename", and "quit".  The resulting behavior for each
 # of these values is as follows:
 #
 # * "delete":
 #   The preexisting directory is deleted and a new directory (having the
 #   same name as the original preexisting directory) is created.
 #
+# * "upgrade":
+#   save a copy and then upgrade the preexisting $EXPDIR directory
+#   keep intact for other preexisting directories
+
 # * "rename":
 #   The preexisting directory is renamed and a new directory (having the
 #   same name as the original preexisting directory) is created.  The new
diff --git a/ush/source_util_funcs.sh b/ush/source_util_funcs.sh
index 1ebe07aff..65bfe90de 100644
--- a/ush/source_util_funcs.sh
+++ b/ush/source_util_funcs.sh
@@ -76,7 +76,7 @@ function source_util_funcs() {
 #
 # Source the file containing the function that checks for preexisting 
 # directories or files and handles them according to a specified method
-# (which can be one of "delete", "rename", and "quit").
+# (which can be one of "delete", "rename", "upgrade" and "quit").
 #
 #-----------------------------------------------------------------------
 #
diff --git a/ush/valid_param_vals.sh b/ush/valid_param_vals.sh
index 8b5769766..784ef59ec 100644
--- a/ush/valid_param_vals.sh
+++ b/ush/valid_param_vals.sh
@@ -42,7 +42,7 @@ valid_vals_FV3GFS_FILE_FMT_LBCS=("nemsio" "grib2")
 valid_vals_GEFS_FILE_FMT_ICS=("grib2")
 valid_vals_GEFS_FILE_FMT_LBCS=("grib2")
 valid_vals_GRID_GEN_METHOD=("GFDLgrid" "ESGgrid")
-valid_vals_PREEXISTING_DIR_METHOD=("delete" "rename" "quit")
+valid_vals_PREEXISTING_DIR_METHOD=("delete" "upgrade" "rename" "quit")
 valid_vals_GTYPE=("regional")
 valid_vals_WRTCMP_output_grid=("rotated_latlon" "lambert_conformal" "regional_latlon")
 valid_vals_RUN_TASK_MAKE_GRID=("TRUE" "true" "YES" "yes" "FALSE" "false" "NO" "no")