diff --git a/README.rst b/README.rst
index 8d37f4b..1f48f27 100644
--- a/README.rst
+++ b/README.rst
@@ -9,7 +9,7 @@ pip install mds-investment
 
 Requires
 ========
-- Tryton 6.0
+- Tryton 6.8
 
 How to
 ======
@@ -22,6 +22,6 @@ You can define the course sources yourself.
 Changes
 =======
 
-*6.0.0 - 09.11.2022*
+*6.8.24 - 07.06.2023*
 
-- init
+- portet to Tryton 6.8
diff --git a/asset.py b/asset.py
index 03a74e5..d599d7b 100644
--- a/asset.py
+++ b/asset.py
@@ -3,7 +3,7 @@
 # The COPYRIGHT file at the top level of this repository contains the
 # full copyright notices and license terms.
 
-from trytond.model import ModelView, ModelSQL, fields, SymbolMixin
+from trytond.model import ModelView, ModelSQL, fields, SymbolMixin, Index
 from trytond.transaction import Transaction
 from trytond.pool import Pool
 from trytond.pyson import Eval, Bool, If, Date
@@ -69,7 +69,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
         'get_rate_data', searcher='search_date')
 
     currency = fields.Many2One(
-        string='Currency', select=True, required=True,
+        string='Currency', required=True,
         model_name='currency.currency', ondelete='RESTRICT')
     currency_digits = fields.Integer(
         string='Digits', required=True,
@@ -159,6 +159,21 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
         super(Asset, cls).__setup__()
         cls._order.insert(0, ('name', 'ASC'))
         cls._order.insert(0, ('date', 'DESC'))
+        t = cls.__table__()
+        cls._sql_indexes.update({
+            Index(
+                t,
+                (t.product, Index.Equality())),
+            Index(
+                t,
+                (t.currency, Index.Equality())),
+            Index(
+                t,
+                (t.uom, Index.Equality())),
+            Index(
+                t,
+                (t.updtdays, Index.Equality())),
+            })
 
     @classmethod
     def migrate_updtsource(cls, module_name):
@@ -912,11 +927,11 @@ class AssetSourceRel(ModelSQL):
     __name__ = 'investment.asset_source_rel'
 
     source = fields.Many2One(
-        string='Online Source', select=True,
+        string='Online Source',
         required=True, model_name='investment.source',
         ondelete='CASCADE')
     asset = fields.Many2One(
-        string='Asset', select=True,
+        string='Asset',
         required=True, model_name='investment.asset',
         ondelete='CASCADE')
 
diff --git a/rate.py b/rate.py
index 0aab598..eef697c 100644
--- a/rate.py
+++ b/rate.py
@@ -4,7 +4,7 @@
 # full copyright notices and license terms.
 
 from trytond.model import (
-        ModelView, ModelSQL, fields, Unique, Check, SymbolMixin)
+        ModelView, ModelSQL, fields, Unique, Check, SymbolMixin, Index)
 from trytond.transaction import Transaction
 from trytond.pool import Pool
 from trytond.pyson import Eval
@@ -15,11 +15,11 @@ class Rate(SymbolMixin, ModelSQL, ModelView):
     __name__ = 'investment.rate'
 
     asset = fields.Many2One(
-        string='Asset', required=True, select=True, ondelete='CASCADE',
+        string='Asset', required=True, ondelete='CASCADE',
         model_name='investment.asset')
-    date = fields.Date(string='Date', required=True, select=True)
+    date = fields.Date(string='Date', required=True)
     rate = fields.Numeric(
-        string='Rate', required=True, select=True,
+        string='Rate', required=True,
         digits=(16, Eval('asset_digits', 4)), depends=['asset_digits'])
 
     asset_digits = fields.Function(fields.Integer(
@@ -46,6 +46,14 @@ class Rate(SymbolMixin, ModelSQL, ModelView):
                 'currency.msg_rate_positive'),
             ]
         cls._order.insert(0, ('date', 'DESC'))
+        cls._sql_indexes.update({
+            Index(
+                t,
+                (t.date, Index.Range(order='DESC'))),
+            Index(
+                t,
+                (t.rate, Index.Range())),
+            })
 
     @classmethod
     def default_date(cls):
diff --git a/setup.py b/setup.py
index 2b79c37..58979c0 100644
--- a/setup.py
+++ b/setup.py
@@ -40,7 +40,7 @@ with open(path.join(here, 'versiondep.txt'), encoding='utf-8') as f:
 
 # tryton-version
 major_version = 6
-minor_version = 0
+minor_version = 8
 
 requires = ['requests>=2.26', 'html2text']
 for dep in info.get('depends', []):
@@ -91,6 +91,7 @@ setup(
         'License :: OSI Approved :: GNU General Public License (GPL)',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
+        'Programming Language :: Python :: 3.9',
     ],
 
     keywords='tryton investment shares commodities',
diff --git a/tests/__init__.py b/tests/__init__.py
index 27a7d83..4effdfa 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -1,17 +1,2 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
-
-import trytond.tests.test_tryton
-import unittest
-
-from .test_module import InvestmentTestCase
-
-
-__all__ = ['suite']
-
-
-def suite():
-    suite = trytond.tests.test_tryton.suite()
-    suite.addTests(unittest.TestLoader().loadTestsFromTestCase(
-        InvestmentTestCase))
-    return suite
diff --git a/tryton.cfg b/tryton.cfg
index 9f0f95f..4ba63f6 100644
--- a/tryton.cfg
+++ b/tryton.cfg
@@ -1,5 +1,5 @@
 [tryton]
-version=6.0.0
+version=6.8.24
 depends:
     ir
     res