diff --git a/Cargo.lock b/Cargo.lock
index 201536158fbb54a8660aef9000a1cacd314bc5c8..b6702471066fae296a42dc41381f50f194b4a1bd 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1064,7 +1064,7 @@ checksum = "79c56d6a0b07f9e19282511c83fc5b086364cbae4ba8c7d5f190c3d9b0425a48"
 
 [[package]]
 name = "medal"
-version = "1.5.1"
+version = "1.5.3"
 dependencies = [
  "bcrypt",
  "csv",
diff --git a/Cargo.toml b/Cargo.toml
index c15e1b476af4eb75b243ea11dc1ff7eb43f2722e..52e9ecfe63b730cf231ff765bb55ffaf5bbd606f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,5 +1,5 @@
 [package]
-version = "1.5.1"
+version = "1.5.3"
 name = "medal"
 authors = ["Robert Czechowski <czechowski@bwinf.de>", "Daniel Brüning <bruening@bwinf.de>"]
 
diff --git a/src/core.rs b/src/core.rs
index 71478992af298ff29c677327dda9c6ce5e3a57b1..5edebaa25d6c94497448ece4b6952e34214cbd66 100644
--- a/src/core.rs
+++ b/src/core.rs
@@ -1391,8 +1391,7 @@ pub fn admin_show_participation<T: MedalConnection>(conn: &T, user_id: i32, cont
     fill_user_data(&user, &mut data);
     data.insert("userid".to_string(), to_json(&user.id));
 
-    let participation =
-        conn.get_participation(user.id, contest_id).ok_or(MedalError::AccessDenied)?;
+    let participation = conn.get_participation(user.id, contest_id).ok_or(MedalError::AccessDenied)?;
     data.insert("start_date".to_string(),
                 to_json(&self::time::strftime("%FT%T%z", &self::time::at(participation.start)).unwrap()));
 
diff --git a/src/db_conn.base.rs b/src/db_conn.base.rs
index dd10a36bfca649cdfa1d49b4a9fd43e1f3202964..fc2011a6c390f37af3c5d1f9da3ace4cd0ee860d 100644
--- a/src/db_conn.base.rs
+++ b/src/db_conn.base.rs
@@ -421,6 +421,10 @@ impl MedalConnection for Connection {
 
     //TODO: use session
     fn login_with_code(&self, _session: Option<&str>, logincode: &str) -> Result<String, ()> {
+        if logincode == "" {
+            return Err(());
+        }
+
         let query = "SELECT id
                      FROM session
                      WHERE logincode = $1";
@@ -506,6 +510,10 @@ impl MedalConnection for Connection {
 
     //TODO: use session
     fn create_user_with_groupcode(&self, _session: Option<&str>, groupcode: &str) -> Result<String, ()> {
+        if groupcode == "" {
+            return Err(());
+        }
+
         let query = "SELECT id
                      FROM usergroup
                      WHERE groupcode = $1";
@@ -947,7 +955,8 @@ impl MedalConnection for Connection {
                                 row.get::<_, Option<String>>(16),
                                 row.get::<_, Option<String>>(17)),
                                row.get::<_, Option<i32>>(18),
-                               row.get::<_, Option<String>>(19),
+                               row.get::<_, Option<self::time::Timespec>>(19)
+                                  .map(|ts| self::time::strftime("%FT%T%z", &self::time::at(ts)).unwrap()),
                                points))
                    .unwrap();
             })
@@ -1111,8 +1120,8 @@ impl MedalConnection for Connection {
                      WHERE session = $1
                      AND contest = $2";
         self.query_map_one(query, &[&session_id, &contest_id], |row| Participation { contest: contest_id,
-                                                                                  user: session_id,
-                                                                                  start: row.get(0) })
+                                                                                     user: session_id,
+                                                                                     start: row.get(0) })
             .ok()?
     }
 
diff --git a/src/db_conn_postgres.rs b/src/db_conn_postgres.rs
index 6293c1cb6e1fcef5eac1f4d700625f2ce4097184..e8cb4945118f05ed69b335bc98f566fb703e5165 100644
--- a/src/db_conn_postgres.rs
+++ b/src/db_conn_postgres.rs
@@ -533,6 +533,10 @@ impl MedalConnection for Connection {
 
     //TODO: use session
     fn login_with_code(&self, _session: Option<&str>, logincode: &str) -> Result<String, ()> {
+        if logincode == "" {
+            return Err(());
+        }
+
         let query = "SELECT id
                      FROM session
                      WHERE logincode = $1";
@@ -618,6 +622,10 @@ impl MedalConnection for Connection {
 
     //TODO: use session
     fn create_user_with_groupcode(&self, _session: Option<&str>, groupcode: &str) -> Result<String, ()> {
+        if groupcode == "" {
+            return Err(());
+        }
+
         let query = "SELECT id
                      FROM usergroup
                      WHERE groupcode = $1";
@@ -1059,7 +1067,8 @@ impl MedalConnection for Connection {
                                 row.get::<_, Option<String>>(16),
                                 row.get::<_, Option<String>>(17)),
                                row.get::<_, Option<i32>>(18),
-                               row.get::<_, Option<String>>(19),
+                               row.get::<_, Option<self::time::Timespec>>(19)
+                                  .map(|ts| self::time::strftime("%FT%T%z", &self::time::at(ts)).unwrap()),
                                points))
                    .unwrap();
             })
@@ -1223,8 +1232,8 @@ impl MedalConnection for Connection {
                      WHERE session = $1
                      AND contest = $2";
         self.query_map_one(query, &[&session_id, &contest_id], |row| Participation { contest: contest_id,
-                                                                                  user: session_id,
-                                                                                  start: row.get(0) })
+                                                                                     user: session_id,
+                                                                                     start: row.get(0) })
             .ok()?
     }
 
diff --git a/src/db_conn_sqlite_new.rs b/src/db_conn_sqlite_new.rs
index cdb6291b60b669acedfe92df5d891eb1284bd7d7..4cc28f7390754b2b7109ced5b692f888052bc4ff 100644
--- a/src/db_conn_sqlite_new.rs
+++ b/src/db_conn_sqlite_new.rs
@@ -533,6 +533,10 @@ impl MedalConnection for Connection {
 
     //TODO: use session
     fn login_with_code(&self, _session: Option<&str>, logincode: &str) -> Result<String, ()> {
+        if logincode == "" {
+            return Err(());
+        }
+
         let query = "SELECT id
                      FROM session
                      WHERE logincode = ?1";
@@ -618,6 +622,10 @@ impl MedalConnection for Connection {
 
     //TODO: use session
     fn create_user_with_groupcode(&self, _session: Option<&str>, groupcode: &str) -> Result<String, ()> {
+        if groupcode == "" {
+            return Err(());
+        }
+
         let query = "SELECT id
                      FROM usergroup
                      WHERE groupcode = ?1";
@@ -1059,7 +1067,8 @@ impl MedalConnection for Connection {
                                 row.get::<_, Option<String>>(16),
                                 row.get::<_, Option<String>>(17)),
                                row.get::<_, Option<i32>>(18),
-                               row.get::<_, Option<String>>(19),
+                               row.get::<_, Option<self::time::Timespec>>(19)
+                                  .map(|ts| self::time::strftime("%FT%T%z", &self::time::at(ts)).unwrap()),
                                points))
                    .unwrap();
             })
@@ -1223,8 +1232,8 @@ impl MedalConnection for Connection {
                      WHERE session = ?1
                      AND contest = ?2";
         self.query_map_one(query, &[&session_id, &contest_id], |row| Participation { contest: contest_id,
-                                                                                  user: session_id,
-                                                                                  start: row.get(0) })
+                                                                                     user: session_id,
+                                                                                     start: row.get(0) })
             .ok()?
     }