diff --git a/src/helpers/GroupsHelper.ts b/src/helpers/GroupsHelper.ts
index be22c09..f22fa07 100644
--- a/src/helpers/GroupsHelper.ts
+++ b/src/helpers/GroupsHelper.ts
@@ -5,6 +5,7 @@ import { NewGroup } from "../entities/NewGroup";
 import { time } from "../utils/DateUtils";
 import { GroupSettings } from "../entities/GroupSettings";
 import { existsSync, unlinkSync } from "fs";
+import { PostsHelper } from "./PostsHelper";
 
 /**
  * Groups helper
@@ -536,9 +537,11 @@ export class GroupsHelper {
 	 * 
 	 * @param groupID Target group ID
 	 */
-	public static async GetLastActivity(groupID: number) : Promise<number> {
-		// TODO URGENT : implement
-		return groupID;
+	public static async GetLastActivity(userID: number, groupID: number) : Promise<number> {
+		
+		const lastPost = await PostsHelper.GetGroupPosts(userID, groupID, 0, 1);
+
+		return lastPost.length == 0 ? 0 : lastPost[0].timeCreate;
 	}
 
 	/**
diff --git a/src/helpers/WebappHelper.ts b/src/helpers/WebappHelper.ts
index 3c358e2..f5a0bf6 100644
--- a/src/helpers/WebappHelper.ts
+++ b/src/helpers/WebappHelper.ts
@@ -29,7 +29,7 @@ export class WebappHelper {
 		
 		// Add groups to the list
 		for(const g of groupsList) list.push(new UserMembershipEntry(
-			await GroupsHelper.GetLastActivity(g), g, UserMembershipType.GROUP));
+			await GroupsHelper.GetLastActivity(userID, g), g, UserMembershipType.GROUP));
 
 		// Sort entries by latest activities
 		list.sort((a, b) => b.lastActivity - a.lastActivity);