diff --git a/deploy/truenas_ws.sh b/deploy/truenas_ws.sh
index 33e3dfa0..44eb0f8a 100644
--- a/deploy/truenas_ws.sh
+++ b/deploy/truenas_ws.sh
@@ -43,15 +43,15 @@ _ws_call() {
   _debug "_ws_call arg1" "$1"
   _debug "_ws_call arg2" "$2"
   _debug "_ws_call arg3" "$3"
-  if [ $# -eq 3 ]; then
-    _ws_response=$(midclt --uri "$_ws_uri" -K "$DEPLOY_TRUENAS_APIKEY" call "$1" "$2" "$3")
-  fi
-  if [ $# -eq 2 ]; then
-    _ws_response=$(midclt --uri "$_ws_uri" -K "$DEPLOY_TRUENAS_APIKEY" call "$1" "$2")
-  fi
-  if [ $# -eq 1 ]; then
-    _ws_response=$(midclt --uri "$_ws_uri" -K "$DEPLOY_TRUENAS_APIKEY" call "$1")
-  fi
+
+  # TrueNAS 26.0.0-BETA3 and later need a --plain option for midclt call, detect if it is available
+  _midclt_plain=""
+  case "$(midclt --help 2>/dev/null)" in
+  *--plain*) _midclt_plain="--plain" ;;
+  esac
+
+  _ws_response=$(midclt --uri "$_ws_uri" -K "$DEPLOY_TRUENAS_APIKEY" $_midclt_plain call "$@")
+
   _debug "_ws_response" "$_ws_response"
   printf "%s" "$_ws_response"
   return 0
@@ -256,8 +256,8 @@ truenas_ws_deploy() {
 
   _info "Gather current WebUI certificate..."
   _ws_response="$(_ws_call "system.general.config")"
-  _ui_certificate_id=$(printf "%s" "$_ws_response" | jq -r '."ui_certificate"."id"')
-  _ui_certificate_name=$(printf "%s" "$_ws_response" | jq -r '."ui_certificate"."name"')
+  _ui_certificate_id=$(printf "%s" "$_ws_response" | jq -r '.ui_certificate | if type == "object" then .id else . end')
+  _ui_certificate_name=$(printf "%s" "$_ws_response" | jq -r 'if (.ui_certificate | type) == "object" then .ui_certificate.name else .ui_certificate_name end')
   _info "Current WebUI certificate ID: $_ui_certificate_id"
   _info "Current WebUI certificate name: $_ui_certificate_name"
 
@@ -332,7 +332,7 @@ truenas_ws_deploy() {
 
   _info "Replace WebUI certificate..."
   _ws_response=$(_ws_call "system.general.update" "{\"ui_certificate\": $_new_certid}")
-  _changed_certid=$(printf "%s" "$_ws_response" | jq -r '."ui_certificate"."id"')
+  _changed_certid=$(printf "%s" "$_ws_response" | jq -r '.ui_certificate | if type == "object" then .id else . end')
   if [ "$_changed_certid" != "$_new_certid" ]; then
     _err "WebUI certificate change error.."
     return 5