diff --git a/.hgignore b/.gitignore
similarity index 87%
rename from .hgignore
rename to .gitignore
index e2b39b0..88532e8 100644
--- a/.hgignore
+++ b/.gitignore
@@ -1,4 +1,4 @@
-syntax: glob
+*.pyc
 build/*
 mds_cashbook_bookcategory.egg-info/*
 dist/*
diff --git a/README.rst b/README.rst
index 7b12126..8ef20d6 100644
--- a/README.rst
+++ b/README.rst
@@ -9,11 +9,11 @@ pip install mds-cashbook-bookcategory
 
 Requires
 ========
-- Tryton 6.0
+- Tryton 7.0
 
 Changes
 =======
 
-*6.0.0 - 07.11.2022*
+*7.0.0 - 01.12.2023*
 
-- init
+- compatibilty to Tryton 7.0
diff --git a/__init__.py b/__init__.py
index 11bfdee..e5bafe6 100644
--- a/__init__.py
+++ b/__init__.py
@@ -6,10 +6,13 @@
 from trytond.pool import Pool
 from .category import Category
 from .book import CategoryCashbookRel, Cashbook
+from .ir import Rule
+
 
 def register():
     Pool.register(
         Category,
         Cashbook,
         CategoryCashbookRel,
+        Rule,
         module='cashbook_bookcategory', type_='model')
diff --git a/book.py b/book.py
index 65f0839..ee219a4 100644
--- a/book.py
+++ b/book.py
@@ -3,14 +3,14 @@
 # this repository contains the full copyright notices and license terms.
 
 from trytond.model import ModelSQL, fields
-from trytond.transaction import Transaction
-from trytond.pool import Pool, PoolMeta
+from trytond.pool import PoolMeta
 
 
 class Cashbook(metaclass=PoolMeta):
     __name__ = 'cashbook.book'
 
-    categories = fields.Many2Many(string='Categories',
+    categories = fields.Many2Many(
+        string='Categories',
         relation_name='cashbook.bookcategory-rel',
         origin='cashbook', target='category')
 
@@ -21,9 +21,11 @@ class CategoryCashbookRel(ModelSQL):
     'Category Cashbook Relation'
     __name__ = 'cashbook.bookcategory-rel'
 
-    category = fields.Many2One(string='Category', required=True, select=True,
+    category = fields.Many2One(
+        string='Category', required=True,
         model_name='cashbook.bookcategory', ondelete='CASCADE')
-    cashbook = fields.Many2One(string='Cashbook', required=True, select=True,
+    cashbook = fields.Many2One(
+        string='Cashbook', required=True,
         model_name='cashbook.book', ondelete='CASCADE')
 
 # end CategoryCashbookRel
diff --git a/category.py b/category.py
index 06160cc..7b97dcb 100644
--- a/category.py
+++ b/category.py
@@ -11,31 +11,35 @@ class Category(tree(separator=' / '), ModelSQL, ModelView):
     "Cashbook Category"
     __name__ = "cashbook.bookcategory"
 
-    company = fields.Many2One(string='Company', model_name='company.company',
+    company = fields.Many2One(
+        string='Company', model_name='company.company',
         required=True, ondelete="RESTRICT")
     name = fields.Char(string='Name', required=True, translate=True)
 
-    parent = fields.Many2One(string='Parent', select=True,
-        model_name='cashbook.bookcategory', ondelete='CASCADE',
-        left='left', right='right')
-    childs = fields.One2Many(string='Children', field='parent',
+    parent = fields.Many2One(
+        string='Parent',
+        model_name='cashbook.bookcategory', ondelete='CASCADE')
+    childs = fields.One2Many(
+        string='Children', field='parent',
         model_name='cashbook.bookcategory')
-    left = fields.Integer(string='Left', required=True, select=True)
-    right = fields.Integer(string='Right', required=True, select=True)
+
+    cashbooks = fields.Many2Many(
+        string='Cashbooks',
+        relation_name='cashbook.bookcategory-rel',
+        origin='category', target='cashbook')
+
+    @classmethod
+    def __register__(cls, module_name):
+        super(Category, cls).__register__(module_name)
+        table = cls.__table_handler__(module_name)
+        table.drop_column('left')
+        table.drop_column('right')
 
     @classmethod
     def __setup__(cls):
         super(Category, cls).__setup__()
         cls._order.insert(0, ('rec_name', 'ASC'))
 
-    @staticmethod
-    def default_left():
-        return 0
-
-    @staticmethod
-    def default_right():
-        return 0
-
     @staticmethod
     def default_company():
         return Transaction().context.get('company') or None
diff --git a/category.xml b/category.xml
index eab3ea6..41b5fbb 100644
--- a/category.xml
+++ b/category.xml
@@ -115,7 +115,7 @@
         </record>
         <record model="ir.rule" id="rg_category_rw_owner-1">
             <field name="domain" eval="[
-                ('create_uid.id', '=', Eval('user', {}).get('id', -1)),
+                ('create_uid.id', '=', Eval('user_id', -1)),
                 ]" pyson="1"/>
             <field name="rule_group" ref="rg_category_rw_owner"/>
         </record>
diff --git a/ir.py b/ir.py
new file mode 100644
index 0000000..182092e
--- /dev/null
+++ b/ir.py
@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# This file is part of the cashbook-module from m-ds.de for Tryton.
+# The COPYRIGHT file at the top level of this repository contains the
+# full copyright notices and license terms.
+
+from trytond.pool import PoolMeta
+
+
+class Rule(metaclass=PoolMeta):
+    __name__ = 'ir.rule'
+
+    @classmethod
+    def _context_modelnames(cls):
+        """ list of models to add 'user_id' to context
+        """
+        result = super(Rule, cls)._context_modelnames()
+        return result | {
+            'cashbook.bookcategory',
+        }
+
+# end Rule
diff --git a/locale/de.po b/locale/de.po
index 2372d4e..94fce9d 100644
--- a/locale/de.po
+++ b/locale/de.po
@@ -54,6 +54,10 @@ msgctxt "view:cashbook.bookcategory:"
 msgid "General Information"
 msgstr "Allgemein"
 
+msgctxt "view:cashbook.bookcategory:"
+msgid "Cashbooks"
+msgstr "Kassenbücher"
+
 msgctxt "field:cashbook.bookcategory,name:"
 msgid "Name"
 msgstr "Name"
@@ -78,6 +82,10 @@ msgctxt "field:cashbook.bookcategory,right:"
 msgid "Right"
 msgstr "Rechts"
 
+msgctxt "field:cashbook.bookcategory,cashbooks:"
+msgid "Cashbooks"
+msgstr "Kassenbücher"
+
 
 #################
 # cashbook.book #
diff --git a/locale/en.po b/locale/en.po
index 97cfcf1..7374def 100644
--- a/locale/en.po
+++ b/locale/en.po
@@ -38,6 +38,10 @@ msgctxt "view:cashbook.bookcategory:"
 msgid "General Information"
 msgstr "General Information"
 
+msgctxt "view:cashbook.bookcategory:"
+msgid "Cashbooks"
+msgstr "Cashbooks"
+
 msgctxt "field:cashbook.bookcategory,name:"
 msgid "Name"
 msgstr "Name"
@@ -62,6 +66,10 @@ msgctxt "field:cashbook.bookcategory,right:"
 msgid "Right"
 msgstr "Right"
 
+msgctxt "field:cashbook.bookcategory,cashbooks:"
+msgid "Cashbooks"
+msgstr "Cashbooks"
+
 msgctxt "view:cashbook.book:"
 msgid "Categories"
 msgstr "Categories"
diff --git a/setup.py b/setup.py
index 235b3ab..043ba3f 100644
--- a/setup.py
+++ b/setup.py
@@ -2,7 +2,7 @@
 """
 
 # Always prefer setuptools over distutils
-from setuptools import setup, find_packages
+from setuptools import setup
 # To use a consistent encoding
 from codecs import open
 from os import path
@@ -36,10 +36,10 @@ with open(path.join(here, 'versiondep.txt'), encoding='utf-8') as f:
         l2 = i.strip().split(';')
         if len(l2) < 4:
             continue
-        modversion[l2[0]] = {'min':l2[1], 'max':l2[2], 'prefix':l2[3]}
+        modversion[l2[0]] = {'min': l2[1], 'max': l2[2], 'prefix': l2[3]}
 
 # tryton-version
-major_version = 6
+major_version = 7
 minor_version = 0
 
 requires = []
@@ -51,56 +51,58 @@ for dep in info.get('depends', []):
                 prefix = modversion[dep]['prefix']
 
             if len(modversion[dep]['max']) > 0:
-                requires.append('%s_%s >= %s, <= %s' %
-                    (prefix, dep, modversion[dep]['min'], modversion[dep]['max']))
-            else :
-                requires.append('%s_%s >= %s' %
-                    (prefix, dep, modversion[dep]['min']))
-        else :
-          requires.append('%s_%s >= %s.%s, < %s.%s' %
-                ('trytond', dep, major_version, minor_version,
+                requires.append('%s_%s >= %s, <= %s' % (
+                    prefix, dep, modversion[dep]['min'],
+                    modversion[dep]['max']))
+            else:
+                requires.append('%s_%s >= %s' % (
+                    prefix, dep, modversion[dep]['min']))
+        else:
+            requires.append('%s_%s >= %s.%s, < %s.%s' % (
+                'trytond', dep, major_version, minor_version,
                 major_version, minor_version + 1))
-requires.append('trytond >= %s.%s, < %s.%s' %
-        (major_version, minor_version, major_version, minor_version + 1))
+requires.append('trytond >= %s.%s, < %s.%s' % (
+    major_version, minor_version, major_version, minor_version + 1))
 
-setup(name='%s_%s' % (PREFIX, MODULE),
+setup(
+    name='%s_%s' % (PREFIX, MODULE),
     version=info.get('version', '0.0.1'),
     description='Tryton module to add categories for cashbooks.',
     long_description=long_description,
+    long_description_content_type='text/x-rst',
     url='https://www.m-ds.de/',
+    download_url='https://scmdev.m-ds.de/Tryton/Extra/cashbook_bookcategory',
     author='martin-data services',
     author_email='service@m-ds.de',
     license='GPL-3',
     classifiers=[
-    'Development Status :: 5 - Production/Stable',
-    'Environment :: Plugins',
-    'Framework :: Tryton',
-    'Intended Audience :: Developers',
-    'Intended Audience :: Customer Service',
-    'Intended Audience :: Information Technology',
-    'Intended Audience :: Financial and Insurance Industry',
-    'Topic :: Office/Business',
-    'Topic :: Office/Business :: Financial :: Accounting',
-    'Natural Language :: German',
-    'Natural Language :: English',
-    'Operating System :: OS Independent',
-    'License :: OSI Approved :: GNU General Public License (GPL)',
-    'Programming Language :: Python :: 3.7',
-    'Programming Language :: Python :: 3.8',
+        'Development Status :: 5 - Production/Stable',
+        'Environment :: Plugins',
+        'Framework :: Tryton',
+        'Intended Audience :: Developers',
+        'Intended Audience :: Customer Service',
+        'Intended Audience :: Information Technology',
+        'Intended Audience :: Financial and Insurance Industry',
+        'Topic :: Office/Business',
+        'Topic :: Office/Business :: Financial :: Accounting',
+        'Natural Language :: German',
+        'Natural Language :: English',
+        'Operating System :: OS Independent',
+        '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 category',
     package_dir={'trytond.modules.%s' % MODULE: '.'},
     packages=[
         'trytond.modules.%s' % MODULE,
         ],
     package_data={
-        'trytond.modules.%s' % MODULE: (info.get('xml', [])
-            + ['tryton.cfg', 'locale/*.po', 'tests/*.py',
-                'view/*.xml',
-                'versiondep.txt', 'README.rst']),
+        'trytond.modules.%s' % MODULE: (info.get('xml', []) + [
+            'tryton.cfg', 'locale/*.po', 'tests/*.py',
+            'view/*.xml', 'versiondep.txt', 'README.rst']),
         },
-
     install_requires=requires,
     zip_safe=False,
     entry_points="""
diff --git a/tests/__init__.py b/tests/__init__.py
index ead6f2c..cf7e957 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -1,24 +1,4 @@
-# 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 trytond.modules.cashbook_bookcategory.tests.test_category import CategoryTestCase
-
-
-__all__ = ['suite']
-
-
-class CashbookCategoryTestCase(\
-    CategoryTestCase,\
-    ):
-    'Test cashbook module'
-    module = 'cashbook_bookcategory'
-
-# end CashbookCategoryTestCase
-
-def suite():
-    suite = trytond.tests.test_tryton.suite()
-    suite.addTests(unittest.TestLoader().loadTestsFromTestCase(CashbookCategoryTestCase))
-    return suite
+# -*- coding: utf-8 -*-
+# 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.
diff --git a/tests/test_category.py b/tests/test_category.py
index 9677d39..ddc689d 100644
--- a/tests/test_category.py
+++ b/tests/test_category.py
@@ -3,11 +3,10 @@
 # The COPYRIGHT file at the top level of this repository contains the
 # full copyright notices and license terms.
 
-from trytond.tests.test_tryton import ModuleTestCase, with_transaction
+from trytond.tests.test_tryton import with_transaction
 from trytond.pool import Pool
 from trytond.transaction import Transaction
-from trytond.exceptions import UserError
-from trytond.modules.cashbook.tests import CashbookTestCase
+from trytond.modules.cashbook.tests.test_module import CashbookTestCase
 
 
 class CategoryTestCase(CashbookTestCase):
@@ -22,8 +21,7 @@ class CategoryTestCase(CashbookTestCase):
 
         company = self.prep_company()
         with Transaction().set_context({
-            'company': company.id,
-            }):
+                'company': company.id}):
             categories, = BookCategory.create([{
                 'name': 'Cat 0',
                 'childs': [('create', [{
@@ -56,8 +54,7 @@ class CategoryTestCase(CashbookTestCase):
         types = self.prep_type()
         company = self.prep_company()
         with Transaction().set_context({
-            'company': company.id,
-            }):
+                'company': company.id}):
             category, = BookCategory.create([{
                 'name': 'Cat 0',
                 'childs': [('create', [{
@@ -78,6 +75,11 @@ class CategoryTestCase(CashbookTestCase):
             self.assertEqual(len(book.categories), 1)
             self.assertEqual(book.categories[0].rec_name, 'Cat 0')
 
+            self.assertEqual(len(category.cashbooks), 1)
+            self.assertEqual(
+                category.cashbooks[0].rec_name,
+                'Book 1 | 0.00 usd | Open')
+
             # replace category
             Book.write(*[
                 [book],
@@ -96,3 +98,6 @@ class CategoryTestCase(CashbookTestCase):
             self.assertEqual(len(book.categories), 0)
 
 # end CategoryTestCase
+
+
+del CashbookTestCase
diff --git a/tryton.cfg b/tryton.cfg
index ba1dc2c..8fb9398 100644
--- a/tryton.cfg
+++ b/tryton.cfg
@@ -1,5 +1,5 @@
 [tryton]
-version=6.0.0
+version=7.0.0
 depends:
     cashbook
 xml:
diff --git a/versiondep.txt b/versiondep.txt
index e56514a..afb67b8 100644
--- a/versiondep.txt
+++ b/versiondep.txt
@@ -1,2 +1,2 @@
-cashbook;6.0.19;6.0.999;mds
+cashbook;7.0.31;7.0.999;mds
 
diff --git a/view/category_form.xml b/view/category_form.xml
index 5366dfc..2d6d58d 100644
--- a/view/category_form.xml
+++ b/view/category_form.xml
@@ -12,6 +12,9 @@ full copyright notices and license terms. -->
             <field name="parent"/>
             <field name="childs" colspan="4"/>
         </page>
+        <page string="Cashbooks" name="cashbooks" col="1">
+            <field name="cashbooks"/>
+        </page>
     </notebook>
     <field name="company" invisible="1"/>