diff --git a/cluster/sge.enable.host.queue.sh b/cluster/sge.enable.host.queue.sh
index 8c9f8a0..1d16aca 100755
--- a/cluster/sge.enable.host.queue.sh
+++ b/cluster/sge.enable.host.queue.sh
@@ -8,6 +8,13 @@ readonly NBARGS="${#}"
 ## Test if DEBUG is already defined (by parent script,…)
 [ -z "${DEBUG}" ] && readonly DEBUG=0
 
+# Maco temp file
+readonly MACO_TMP_FILE="/tmp/.maco.upgrade"
+readonly MACO_TMP_URGENT_FILE="/tmp/.maco.urgent.upgrade"
+
+# APT temp file to monitor
+readonly APT_TMP_FILE="/tmp/.apt.upgrade"
+
 ## Colors
 readonly PURPLE='\033[1;35m'
 readonly RED='\033[0;31m'
@@ -20,9 +27,13 @@ manage_args() {                                                 # {{{
 	case "${NBARGS}" in
 		0 )
 			sge_hostname="$(hostname -f)"
+			## Ensure there is no pending upgrades on the local host
+			CHECK_UPGRADE="0"
 			;;
 		1 )
 			sge_hostname="${1}"
+			## No way to monitor pending upgrades on a remote host
+			CHECK_UPGRADE="1"
 			;;
 		* )
 			printf '%b\n' "${RED}Expect 1 or 0 argument.${RESET}"
@@ -61,7 +72,58 @@ debug_message() {                                               # {{{
 
 }
 # }}}
-is_queue_enable() {                                            # {{{
+is_apt_upgrade_present() {                                      # {{{
+
+	## No pending upgrade by default
+	return_apt_upgrade_present="1"
+
+	## If we need to watch for upgrades
+	if [ "${CHECK_UPGRADE}" -eq "0" ]; then
+		### Check if temp APT upgrade file exists
+		if [ -f "${APT_TMP_FILE}" ]; then
+			return_apt_upgrade_present="0"
+			debug_message "is_apt_upgrade_absent − \
+APT upgrade seems available for this system."
+		else
+			return_apt_upgrade_present="1"
+			debug_message "is_apt_upgrade_absent − \
+NO APT upgrade available for this system."
+		fi
+	fi
+
+	return "${return_apt_upgrade_present}"
+
+}
+# }}}
+is_maco_upgrade_present() {                                     # {{{
+
+	## No pending upgrades by default
+	return_maco_upgrade_present="1"
+
+	## If we need to watch for upgrades
+	if [ "${CHECK_UPGRADE}" -eq "0" ]; then
+		## Check if temp Maco upgrade file is present
+		if [ -f "${MACO_TMP_FILE}" ]; then
+			return_maco_upgrade_present="0"
+			debug_message "is_maco_upgrade_present − \
+Maco upgrade seems available."
+
+		## Check if temp Maco urgent upgrade file is present
+		elif [ -f "${MACO_TMP_URGENT_FILE}" ]; then
+			return_maco_upgrade_present="0"
+			debug_message "is_maco_upgrade_present − \
+Maco urgent upgrade seems available."
+		else
+			debug_message "is_maco_upgrade_present − \
+No Maco upgrade require."
+		fi
+	fi
+
+	return "${return_maco_upgrade_present}"
+
+}
+# }}}
+is_queue_enable() {                                             # {{{
 
 	local_queue_enable_hostname="${1}"
 	local_queue_enable_name="${2}"
@@ -129,7 +191,7 @@ state is: ${RED}${local_sge_queue_state:=/dev/null}${COLOR_DEBUG}."
 
 }
 # }}}
-is_all_queue_enable() {                                            # {{{
+is_all_queue_enable() {                                         # {{{
 
 	local_all_queue_enable_hostname="${1}"
 	local_all_queue_enable_name="${2}"
@@ -151,7 +213,7 @@ is_all_queue_enable() {                                            # {{{
 
 }
 # }}}
-enable_sge_queue() {                                           # {{{
+enable_sge_queue() {                                            # {{{
 
 	local_sge_hostname="${1}"
 	local_sge_queue_name="${2}"
@@ -180,6 +242,18 @@ main() {                                                        # {{{
 		| cut -d"'" -f2 \
 		| tr -s '\n' ' ' )"
 
+
+	## If APT package upgrade is available
+	### Exit (wait for APT upgrade to be applied)
+	is_apt_upgrade_present \
+		&& exit 0
+
+	## If Maco upgrade is present
+	### Exit (wait for Maco upgrade to be applied)
+	is_maco_upgrade_present \
+		&& exit 0
+
+
 	## Simple debug message with color to valid current variables
 	debug_message "main − Try to manage \
 SGE queue(s): ${RED}${sge_queues_name_print:=/dev/null}${COLOR_DEBUG}\