diff --git a/backend/src/controllers/learningPaths.ts b/backend/src/controllers/learningPaths.ts
index 50299d0f..e77e4bba 100644
--- a/backend/src/controllers/learningPaths.ts
+++ b/backend/src/controllers/learningPaths.ts
@@ -11,7 +11,7 @@ export async function getLearningPaths(req: Request, res: Response): Promise<voi
         const hruids = req.query.hruid;
         const themeKey = req.query.theme as string;
         const searchQuery = req.query.search as string;
-        const language = (req.query.language as string) || FALLBACK_LANG;
+        const language = (req.query.language as Language) || FALLBACK_LANG;
 
         let hruidList;
 
@@ -28,14 +28,14 @@ export async function getLearningPaths(req: Request, res: Response): Promise<voi
                 return;
             }
         } else if (searchQuery) {
-            const searchResults = await searchLearningPaths(searchQuery, language);
+            const searchResults = await learningPathService.searchLearningPaths(searchQuery, language);
             res.json(searchResults);
             return;
         } else {
             hruidList = themes.flatMap((theme) => theme.hruids);
         }
 
-        const learningPaths = await fetchLearningPaths(hruidList, language, `HRUIDs: ${hruidList.join(', ')}`);
+        const learningPaths = await learningPathService.fetchLearningPaths(hruidList, language, `HRUIDs: ${hruidList.join(', ')}`);
         res.json(learningPaths.data);
     } catch (error) {
         getLogger().error('❌ Unexpected error fetching learning paths:', error);
diff --git a/backend/src/entities/questions/question.entity.ts b/backend/src/entities/questions/question.entity.ts
index bfa0d7bb..18d589ac 100644
--- a/backend/src/entities/questions/question.entity.ts
+++ b/backend/src/entities/questions/question.entity.ts
@@ -14,8 +14,8 @@ export class Question {
     })
     learningObjectLanguage!: Language;
 
-    @PrimaryKey({ type: 'string' })
-    learningObjectVersion: string = '1';
+    @PrimaryKey({ type: 'number' })
+    learningObjectVersion: number = 1;
 
     @PrimaryKey({ type: 'integer' })
     sequenceNumber!: number;
diff --git a/backend/src/interfaces/learning-content.ts b/backend/src/interfaces/learning-content.ts
index 997865ef..51474917 100644
--- a/backend/src/interfaces/learning-content.ts
+++ b/backend/src/interfaces/learning-content.ts
@@ -91,7 +91,7 @@ export interface FilteredLearningObject {
     htmlUrl: string;
     language: Language;
     difficulty: number;
-    estimatedTime: number;
+    estimatedTime?: number;
     available: boolean;
     teacherExclusive: boolean;
     educationalGoals: EducationalGoal[];