diff --git a/helpers/helpers.v2.1.d/mongodb b/helpers/helpers.v2.1.d/mongodb
index 370b88d92..16d91e920 100644
--- a/helpers/helpers.v2.1.d/mongodb
+++ b/helpers/helpers.v2.1.d/mongodb
@@ -214,6 +214,7 @@ ynh_mongo_remove_db() {
 }
 
 # Install MongoDB and integrate MongoDB service in YunoHost
+# It can upgrade / downgrade the desired mongo version to ensure a compatible one is installed
 #
 # The installed version is defined by $mongo_version which should be defined as global prior to calling this helper
 #
@@ -235,7 +236,37 @@ ynh_install_mongo() {
         mongo_debian_release=buster
     fi
 
-    ynh_install_extra_app_dependencies --repo="deb http://repo.mongodb.org/apt/debian $mongo_debian_release/mongodb-org/$mongo_version main" --package="mongodb-org mongodb-org-server mongodb-org-tools mongodb-mongosh" --key="https://www.mongodb.org/static/pgp/server-$mongo_version.asc"
+	if [[ "$mongo_debian_release" == "bookworm" && "$mongo_version" != "7."* ]]; then
+		ynh_print_warn --message="Switched to Mongo v7 as $mongo_version is not compatible with $mongo_debian_release"
+		mongo_version = "7.0"
+	fi
+
+	# Check if MongoDB is already installed
+	local install_package=true
+	local current_version=$(ynh_package_version --package="mongodb-org-server")
+	# Focus only the major, minor versions
+	current_version=$(cut -c 1-3 <<< "$current_version")
+	
+	if [[ "a$current_version" != "a" ]]; then
+		if (( $(bc <<< "$current_version < $mongo_version") )); then
+			if (( $(bc <<< "scale = 0 ; x = $mongo_version / 1 - $current_version / 1; x > 1.0" ))); then
+				# Mongo only support upgrading a major version to another
+				ynh_print_err --message="Upgrading Mongo from version  $current_version to $mongo_version is not supported"
+				install_package=false
+			else
+				ynh_print_info --message="Upgrading Mongo from version $current_version to $mongo_version"
+			fi
+		else
+			if (( $(bc <<< "$current_version >= $mongo_version") )); then
+				ynh_print_warn --message="Mongo version $current_version is already installed and will be kept instead of requested version $mongo_version"
+				install_package=false
+			fi
+		fi
+	fi
+
+	if [[ "$install_package" = true ]]; then
+        ynh_install_extra_app_dependencies --repo="deb http://repo.mongodb.org/apt/debian $mongo_debian_release/mongodb-org/$mongo_version main" --package="mongodb-org mongodb-org-server mongodb-org-tools mongodb-mongosh" --key="https://www.mongodb.org/static/pgp/server-$mongo_version.asc"
+    fi
     mongodb_servicename=mongod
 
     # Make sure MongoDB is started and enabled