diff --git a/src/components/sites/singleGroupSite/singleGroupSite.tsx b/src/components/sites/singleGroupSite/singleGroupSite.tsx
index 221433465e06223274b85e3f8dcefb4e6fae0e52..b0ac8d924e801aacc4ca20ee5bb80d283d251992 100644
--- a/src/components/sites/singleGroupSite/singleGroupSite.tsx
+++ b/src/components/sites/singleGroupSite/singleGroupSite.tsx
@@ -118,7 +118,7 @@ class SingleGroupSite extends React.Component<Props & RouteComponentProps<Matche
                   <h1 className="clear-margin">
                     {
                       this.props.group &&
-                      this.props.group.displayName
+                      this.props.group.displayName + ` (id: ${this.props.group.id})`
                     }
                   </h1>
 
diff --git a/src/constants.ts b/src/constants.ts
index b20edfcfb06bc8242238737846817a4eab1e41b3..3c8c840c933115aa50027ec84eaa02377195a314 100644
--- a/src/constants.ts
+++ b/src/constants.ts
@@ -13,7 +13,7 @@ import Logger from './helpers/logger'
  * y - breaking changes / new features
  * z - fixes, small changes
  */
-export const versionString = '2.19.4'
+export const versionString = '2.19.5'
 
 
 export const supportMail = 'yapex@informatik.uni-halle.de'
diff --git a/src/helpers/jsonTransformer.ts b/src/helpers/jsonTransformer.ts
index a0e3e9b156798fbe50f29bcc05acfbcabeeae16f..676403c4eb22027ccd9cbe9f241ced4ca9a343a5 100644
--- a/src/helpers/jsonTransformer.ts
+++ b/src/helpers/jsonTransformer.ts
@@ -76,7 +76,7 @@ const reMsAjax = /^\/Date\((d|-|.*)\)[\/|\\]$/
 const reWithoutMs = /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2})Z?$/
 
 /**
- * same as dateTimeReviver but converts the time to local time (was gtm +2)
+ * same as dateTimeReviver but converts the (server) time to local time (add utc offset)
  * @param key
  * @param value
  * @returns {any}
diff --git a/src/types/exerciseRelease.ts b/src/types/exerciseRelease.ts
index 002c4b4a1574a3f572e469070ca8342ad3267535..f28405a499e2da8340dda7f7563e33d3da0a5936 100644
--- a/src/types/exerciseRelease.ts
+++ b/src/types/exerciseRelease.ts
@@ -195,9 +195,9 @@ export interface ExerciseReleaseForBackend extends ExerciseReleaseBase {
   /**
    * the automatic starting date time (if the release type is automatic)
    */
-  readonly automaticStartAt?: Date
+  readonly automaticStartAt?: Date | null
   /**
    * the automatic ending date time (if the release type is automatic)
    */
-  readonly automaticEndAt?: Date
+  readonly automaticEndAt?: Date | null
 }