diff --git a/models/users.model b/models/users.model
index 657669910..740de8186 100644
--- a/models/users.model
+++ b/models/users.model
@@ -58,8 +58,9 @@ StudyFeatures  -- multiple entries possible for students pursuing several degree
     superField    StudyTermsId Maybe
     type          StudyFieldType  -- Major or minor, i.e. Haupt-/Nebenfach
     semester      Int
-    updated       UTCTime default=now() -- last update from LDAP
-    valid         Bool default=true       -- marked as active in LDAP (students may switch, but LDAP never forgets)
+    firstObserved UTCTime Maybe
+    lastObserved  UTCTime default=now() -- last update from LDAP
+    valid         Bool default=true
     UniqueStudyFeatures user degree field type semester
     deriving Eq Show
     -- UniqueUserSubject ubuser degree field -- There exists a counterexample
diff --git a/src/Foundation/Yesod/Auth.hs b/src/Foundation/Yesod/Auth.hs
index 66941c9f6..8be3e80b9 100644
--- a/src/Foundation/Yesod/Auth.hs
+++ b/src/Foundation/Yesod/Auth.hs
@@ -321,7 +321,7 @@ upsertCampusUser plugin ldapData = do
           , Just defType   <- studyTermsDefaultType
             -> do
               $logDebugS "Campus" [st|Applying default for standalone study term “#{tshow subterm}”|]
-              (:) (StudyFeatures userId defDegree subterm Nothing defType subSemester now True) <$> assimilateSubTerms subterms unusedFeats
+              (:) (StudyFeatures userId defDegree subterm Nothing defType subSemester (Just now) now True) <$> assimilateSubTerms subterms unusedFeats
         Nothing
           | [] <- unusedFeats -> do
               $logDebugS "Campus" [st|Saw subterm “#{tshow subterm}” when no fos-terms remain|]
@@ -389,26 +389,11 @@ upsertCampusUser plugin ldapData = do
   forM_ fs $ \f@StudyFeatures{..} -> do
     insertMaybe studyFeaturesDegree $ StudyDegree (unStudyDegreeKey studyFeaturesDegree) Nothing Nothing
     insertMaybe studyFeaturesField $ StudyTerms (unStudyTermsKey studyFeaturesField) Nothing Nothing Nothing Nothing
-    oldFs <- selectKeysList
-      [ StudyFeaturesUser ==. studyFeaturesUser
-       , StudyFeaturesDegree ==. studyFeaturesDegree
-       , StudyFeaturesField ==. studyFeaturesField
-       , StudyFeaturesType ==. studyFeaturesType
-       , StudyFeaturesSemester ==. studyFeaturesSemester
-       ]
-      []
-    case oldFs of
-      [oldF] -> update oldF
-        [ StudyFeaturesUpdated =. now
-        , StudyFeaturesValid =. True
-        , StudyFeaturesField =. studyFeaturesField
-        , StudyFeaturesSuperField =. studyFeaturesSuperField
-        ]
-      _other -> void $ upsert f
-        [ StudyFeaturesUpdated =. now
-        , StudyFeaturesValid =. True
-        , StudyFeaturesSuperField =. studyFeaturesSuperField
-        ]
+    void $ upsert f
+      [ StudyFeaturesLastObserved =. now
+      , StudyFeaturesValid =. True
+      , StudyFeaturesSuperField =. studyFeaturesSuperField
+      ]
   associateUserSchoolsByTerms userId
 
   let
diff --git a/src/Handler/Utils/StudyFeatures.hs b/src/Handler/Utils/StudyFeatures.hs
index 52d59082f..80d7d1681 100644
--- a/src/Handler/Utils/StudyFeatures.hs
+++ b/src/Handler/Utils/StudyFeatures.hs
@@ -24,7 +24,7 @@ parseSubTermsSemester = parse (pLMUTermsSemester <* eof) (unpack key)
 
 
 pStudyFeatures :: UserId -> UTCTime -> Parser [StudyFeatures]
-pStudyFeatures studyFeaturesUser studyFeaturesUpdated = do
+pStudyFeatures studyFeaturesUser now = do
   studyFeaturesDegree <- StudyDegreeKey' <$> pKey
   void $ string "$$"
 
@@ -41,6 +41,8 @@ pStudyFeatures studyFeaturesUser studyFeaturesUpdated = do
       studyFeaturesSemester <- decimal
       let studyFeaturesValid = True
           studyFeaturesSuperField = Nothing
+          studyFeaturesFirstObserved = Just now
+          studyFeaturesLastObserved = now
       return StudyFeatures{..}
 
   pStudyFeature `sepBy1` char '#'
diff --git a/src/Model/Migration.hs b/src/Model/Migration.hs
index 5ebd46b6f..6b74de437 100644
--- a/src/Model/Migration.hs
+++ b/src/Model/Migration.hs
@@ -913,6 +913,14 @@ customMigrations = Map.fromListWith (>>)
           insert_ CronLastExec{ cronLastExecJob = toJSON $ JobQueueNotification NotificationAllocationUnratedApplications{..}, .. }
 
     )
+  , ( AppliedMigrationKey [migrationVersion|39.0.0|] [version|40.0.0|]
+    , whenM (tableExists "study_features") $ do
+        [executeQQ|
+          ALTER TABLE study_features RENAME updated TO last_observed;
+          ALTER TABLE study_features ADD COLUMN first_observed timestamp with time zone;
+          UPDATE study_features SET first_observed = (SELECT MAX(last_observed) FROM study_features as other WHERE other."user" = study_features."user" AND other.degree = study_features.degree AND other.field = study_features.field AND other.type = study_features.type AND other.semester = study_features.semester - 1);
+        |]
+    )
   ]
 
 
diff --git a/templates/course/user/profile.hamlet b/templates/course/user/profile.hamlet
index 20b3417e0..2b375a22d 100644
--- a/templates/course/user/profile.hamlet
+++ b/templates/course/user/profile.hamlet
@@ -44,14 +44,18 @@ $newline never
                 <th .table__th>_{MsgStudyFeatureAge}
                 <th .table__th>_{MsgStudyFeatureValid}
                 <th .table__th>_{MsgStudyFeatureUpdate}
-              $forall ((Entity _ StudyFeatures{studyFeaturesType, studyFeaturesSemester, studyFeaturesValid, studyFeaturesUpdated}), (Entity _ degree), (Entity _ field)) <- studies
+              $forall ((Entity _ StudyFeatures{studyFeaturesType, studyFeaturesSemester, studyFeaturesValid, studyFeaturesFirstObserved, studyFeaturesLastObserved}), (Entity _ degree), (Entity _ field)) <- studies
                 <tr .table__row>
                   <td .table__td>_{field}
                   <td .table__td>_{degree}
                   <td .table__td>_{studyFeaturesType}
                   <td .table__td>#{studyFeaturesSemester}
                   <td .table__td>#{hasTickmark studyFeaturesValid}
-                  <td .table__td>^{formatTimeW SelFormatDate studyFeaturesUpdated}
+                  <td .table__td>
+                    $maybe fObs <- studyFeaturesFirstObserved
+                      ^{formatTimeRangeW SelFormatDate fObs $ Just studyFeaturesLastObserved}
+                    $nothing
+                      ^{formatTimeW SelFormatDate studyFeaturesLastObserved}
       $maybe _ <- mRegistration
         <dt .deflist__dt>_{MsgCourseStudyFeature}
         <dd .deflist__dd>^{regFieldWidget}
diff --git a/templates/profileData.hamlet b/templates/profileData.hamlet
index fe327abe3..231082dbc 100644
--- a/templates/profileData.hamlet
+++ b/templates/profileData.hamlet
@@ -43,14 +43,18 @@ $newline never
               <th .table__th>_{MsgStudyFeatureValid}
               <th .table__th>_{MsgStudyFeatureUpdate}
 
-            $forall ((Entity _ StudyFeatures{studyFeaturesType, studyFeaturesSemester, studyFeaturesValid, studyFeaturesUpdated}), (Entity _ degree), (Entity _ field)) <- studies
+            $forall ((Entity _ StudyFeatures{studyFeaturesType, studyFeaturesSemester, studyFeaturesValid, studyFeaturesFirstObserved, studyFeaturesLastObserved}), (Entity _ degree), (Entity _ field)) <- studies
               <tr.table__row>
                 <td .table__td>_{field}
                 <td .table__td>_{degree}
                 <td .table__td>_{studyFeaturesType}
                 <td .table__td>#{studyFeaturesSemester}
                 <td .table__td>#{hasTickmark studyFeaturesValid}
-                <td .table__td>^{formatTimeW SelFormatDateTime studyFeaturesUpdated}
+                <td .table__td>
+                  $maybe fObs <- studyFeaturesFirstObserved
+                    ^{formatTimeRangeW SelFormatDateTime fObs $ Just studyFeaturesLastObserved}
+                  $nothing
+                    ^{formatTimeW SelFormatDateTime studyFeaturesLastObserved}
 <section>
   <div .container>
     $if hasRows