diff --git a/README.rst b/README.rst
index 6a3e8a4..f197171 100644
--- a/README.rst
+++ b/README.rst
@@ -9,7 +9,7 @@ pip install mds-cashbook-report
 
 Requires
 ========
-- Tryton 6.0
+- Tryton 6.8
 
 Info
 ====
@@ -29,6 +29,7 @@ so that you can display several evaluations at the same time.
 Changes
 =======
 
-*6.0.0 - 28.10.2022*
+*6.8.8 - 16.06.2023*
+
+- compatibility to Tryton 6.8
 
-- init
diff --git a/line.py b/line.py
index d4e4ab4..c266820 100644
--- a/line.py
+++ b/line.py
@@ -19,29 +19,25 @@ class EvaluationLine(ModelSQL, ModelView):
     __name__ = 'cashbook_report.eval_line'
 
     evaluation = fields.Many2One(
-        string='Evaluation', required=True,
-        select=True, ondelete='CASCADE',
+        string='Evaluation', required=True, ondelete='CASCADE',
         model_name='cashbook_report.evaluation')
     cashbook = fields.Many2One(
-        string='Cashbook', select=True, ondelete='CASCADE',
-        model_name='cashbook.book',
+        string='Cashbook', ondelete='CASCADE', model_name='cashbook.book',
         states={
             'required': Eval('eval_dtype', '').in_(cashbook_types),
         }, depends=['eval_dtype'])
     dtype = fields.Many2One(
-        string='Type', select=True, ondelete='CASCADE',
-        model_name='cashbook.type',
+        string='Type', ondelete='CASCADE', model_name='cashbook.type',
         states={
             'required': Eval('eval_dtype', '').in_(booktype_types),
         }, depends=['eval_dtype'])
     currency = fields.Many2One(
-        string='Currency', select=True, ondelete='CASCADE',
-        model_name='currency.currency',
+        string='Currency', ondelete='CASCADE', model_name='currency.currency',
         states={
             'required': Eval('eval_dtype', '') == 'currencies',
         }, depends=['eval_dtype'])
     category = fields.Many2One(
-        string='Category', select=True, ondelete='CASCADE',
+        string='Category', ondelete='CASCADE',
         model_name='cashbook.bookcategory',
         states={
             'required': Eval('eval_dtype', '').in_(category_types),
diff --git a/setup.py b/setup.py
index f77e4eb..b2bd2ec 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 = []
 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 cashbook report',
diff --git a/tests/__init__.py b/tests/__init__.py
index 5180a5b..cf7e957 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -2,17 +2,3 @@
 # This file is part of the cashbook-module from m-ds for 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 trytond.modules.cashbook_report.tests.test_report import ReportTestCase
-
-
-__all__ = ['suite']
-
-
-def suite():
-    suite = trytond.tests.test_tryton.suite()
-    suite.addTests(unittest.TestLoader().loadTestsFromTestCase(ReportTestCase))
-    return suite
diff --git a/tests/test_report.py b/tests/test_report.py
index 463e933..a9b0f7f 100644
--- a/tests/test_report.py
+++ b/tests/test_report.py
@@ -7,7 +7,7 @@ from trytond.tests.test_tryton import with_transaction, activate_module
 from trytond.pool import Pool
 from trytond.transaction import Transaction
 from trytond.exceptions import UserError
-from trytond.modules.cashbook_investment.tests import \
+from trytond.modules.cashbook_investment.tests.test_module import \
     CashbookInvestmentTestCase
 from datetime import date
 from decimal import Decimal
@@ -705,8 +705,8 @@ class ReportTestCase(CashbookInvestmentTestCase):
             # must fail
             self.assertRaisesRegex(
                 UserError,
-                'A value is required for field "Data type" in ' +
-                '"Evaluation Line Relation".',
+                'A value is required for field "Data type" in "None" ' +
+                'of "Evaluation Line Relation".',
                 Evaluation.create,
                 [{
                     'name': 'Evaluation 1',
@@ -723,8 +723,8 @@ class ReportTestCase(CashbookInvestmentTestCase):
             # must fail
             self.assertRaisesRegex(
                 UserError,
-                'A value is required for field "Cashbook" in ' +
-                '"Evaluation Line Relation".',
+                'A value is required for field "Cashbook" in "None" ' +
+                'of "Evaluation Line Relation".',
                 Evaluation.create,
                 [{
                     'name': 'Evaluation 3',
diff --git a/tryton.cfg b/tryton.cfg
index 4d73694..4cd93b9 100644
--- a/tryton.cfg
+++ b/tryton.cfg
@@ -1,5 +1,5 @@
 [tryton]
-version=6.0.0
+version=6.8.8
 depends:
     res
     cashbook
diff --git a/versiondep.txt b/versiondep.txt
index 4605d4c..2ac9efb 100644
--- a/versiondep.txt
+++ b/versiondep.txt
@@ -1,2 +1,2 @@
-cashbook;6.0.19;6.0.999;mds
-cashbook_bookcategory;6.0.2;6.0.999;mds
+cashbook;6.8.28;6.8.999;mds
+cashbook_bookcategory;6.8.4;6.8.999;mds