diff --git a/seminar/migrations/0010_alter_rok_maturity.py b/seminar/migrations/0010_alter_rok_maturity.py
new file mode 100644
index 00000000..58c099fb
--- /dev/null
+++ b/seminar/migrations/0010_alter_rok_maturity.py
@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('seminar', '0009_rename_imported_IDs'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='resitel',
+            name='rok_maturity',
+            field=models.IntegerField(null=True, verbose_name='rok maturity', blank=True),
+            preserve_default=True,
+        ),
+    ]
diff --git a/seminar/migrations/0011_alter_timestamp_def.py b/seminar/migrations/0011_alter_timestamp_def.py
new file mode 100644
index 00000000..238386a6
--- /dev/null
+++ b/seminar/migrations/0011_alter_timestamp_def.py
@@ -0,0 +1,39 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+import django.utils.timezone
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('seminar', '0010_alter_rok_maturity'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='prilohareseni',
+            name='timestamp',
+            field=models.DateTimeField(default=django.utils.timezone.now, verbose_name='vytvo\u0159eno', editable=False, blank=True),
+            preserve_default=True,
+        ),
+        migrations.AlterField(
+            model_name='problem',
+            name='import_dakos_id',
+            field=models.CharField(default=b'', help_text='ID z importu z DAKOSU s prefixem podle p\u016fvodu: "AZAD:xxx (MAMOPER.MM_AZAD), ""DOZ:xxx" (MAMOPER.MM_DOZ), "ZAD:rocnik.cislo.uloha.typ" (MAMOPER.MM_ZADANIA), "ULOHA:xxx" (MAMOPER.MM_ULOHY)', max_length=32, verbose_name='importovan\xe9 ID s typem', blank=True),
+            preserve_default=True,
+        ),
+        migrations.AlterField(
+            model_name='problem',
+            name='timestamp',
+            field=models.DateTimeField(default=django.utils.timezone.now, verbose_name='vytvo\u0159eno', editable=False, blank=True),
+            preserve_default=True,
+        ),
+        migrations.AlterField(
+            model_name='reseni',
+            name='timestamp',
+            field=models.DateTimeField(default=django.utils.timezone.now, verbose_name='vytvo\u0159eno', editable=False, blank=True),
+            preserve_default=True,
+        ),
+    ]
diff --git a/seminar/models.py b/seminar/models.py
index 4818327f..bb5c9ea9 100644
--- a/seminar/models.py
+++ b/seminar/models.py
@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 import os
-import datetime
 import random
 
 from django.db import models
@@ -130,7 +129,7 @@ class Resitel(SeminarModelBase):
     skola = models.ForeignKey(Skola, blank=True, null=True, verbose_name=u'škola')
 
     # Očekávaný rok maturity a vyřazení z aktivních řešitelů
-    rok_maturity = models.IntegerField(u'rok maturity')
+    rok_maturity = models.IntegerField(u'rok maturity', blank=True, null=True)
 
     email = models.EmailField(u'e-mail', max_length=256, blank=True, default='')
 
@@ -332,12 +331,12 @@ class Problem(SeminarModelBase):
 
     body = models.IntegerField(u'maximum bodů', blank=True, null=True)
 
-    timestamp = models.DateTimeField(u'vytvořeno', auto_now=True)
+    timestamp = models.DateTimeField(u'vytvořeno', default=timezone.now, blank=True, editable=False)
 
     # Staré (do 2014) ID problému z DAKOSU -- jen u importovaných záznamů
     import_dakos_id = models.CharField(u'importované ID s typem', max_length=32, blank=True, default='',
         help_text=(u'ID z importu z DAKOSU s prefixem podle původu: "AZAD:xxx (MAMOPER.MM_AZAD), "' + 
-        u'"DOZ:xxx" (MAMOPER.MM_DOZ), "ZAD:rocnik.cislo.uloha.typ" (MAMOPER.MM_ZADANIA)'))
+        u'"DOZ:xxx" (MAMOPER.MM_DOZ), "ZAD:rocnik.cislo.uloha.typ" (MAMOPER.MM_ZADANIA), "ULOHA:xxx" (MAMOPER.MM_ULOHY)'))
 
     def __str__(self):
         return force_unicode(u'%s (%s)' % (self.nazev, self.stav))
@@ -378,7 +377,7 @@ class Reseni(SeminarModelBase):
 
     cislo_body = models.ForeignKey(Cislo, verbose_name=u'číslo pro body', related_name='bodovana_reseni', blank=True, null=True)
 
-    timestamp = models.DateTimeField(u'vytvořeno', auto_now=True)
+    timestamp = models.DateTimeField(u'vytvořeno', default=timezone.now, blank=True, editable=False)
 
     FORMA_PAPIR = 'papir'
     FORMA_EMAIL = 'email'
@@ -400,9 +399,9 @@ class Reseni(SeminarModelBase):
 # PrilohaReseni method
 def generate_filename(self, filename):
     clean = filename.replace('/','-').replace('\0', '')
-    datedir = datetime.datetime.now().strftime('%Y-%m')
+    datedir = timezone.now().strftime('%Y-%m')
     fname = "%s_%s" % (
-        datetime.datetime.now().strftime('%Y-%m-%d-%H:%M'),
+        timezone.now().strftime('%Y-%m-%d-%H:%M'),
         clean)
     return os.path.join(settings.SEMINAR_RESENI_DIRNAME, datedir, fname)
 
@@ -422,7 +421,7 @@ class PrilohaReseni(SeminarModelBase):
 
     reseni = models.ForeignKey(Reseni, verbose_name=u'řešení', related_name='prilohy')
 
-    timestamp = models.DateTimeField(u'vytvořeno', auto_now=True)
+    timestamp = models.DateTimeField(u'vytvořeno', default=timezone.now, blank=True, editable=False)
 
     soubor = models.FileField(u'soubor', upload_to = generate_filename)