diff --git a/.drone.yml b/.drone.yml
index 67aa49b..82ae06b 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -32,15 +32,15 @@ services:
 
 matrix:
     include:
-        - IMAGE: python:2.7
-          TOXENV: py27
-          DATABASE: sqlite
-        - IMAGE: python:2.7
-          TOXENV: py27
-          DATABASE: postgresql
         - IMAGE: python:3.6
           TOXENV: py36
           DATABASE: sqlite
         - IMAGE: python:3.6
           TOXENV: py36
           DATABASE: postgresql
+        - IMAGE: python:3.7
+          TOXENV: py37
+          DATABASE: sqlite
+        - IMAGE: python:3.7
+          TOXENV: py37
+          DATABASE: postgresql
\ No newline at end of file
diff --git a/INSTALL b/INSTALL
index 34b02e2..a3d4b54 100644
--- a/INSTALL
+++ b/INSTALL
@@ -4,7 +4,6 @@ Installing datalife_ir_sequence_period
 Prerequisites
 -------------
 
- * Python 2.7 or later (http://www.python.org/)
  * trytond (http://www.tryton.org/)
 
 Installation
diff --git a/ir.py b/ir.py
index 36b1143..58f7793 100644
--- a/ir.py
+++ b/ir.py
@@ -1,6 +1,6 @@
 # The COPYRIGHT file at the top level of this repository contains the full
 # copyright notices and license terms.
-from itertools import izip
+
 from trytond.model import ModelSQL, ModelView, MatchMixin, fields
 from trytond.pool import PoolMeta, Pool
 from trytond.pyson import Eval, And, Bool
@@ -13,9 +13,8 @@ __all__ = ['Sequence', 'SequencePeriod', 'SequenceStrict']
 sql_sequence = backend.get('Database').has_sequence()
 
 
-class Sequence:
+class Sequence(metaclass=PoolMeta):
     __name__ = 'ir.sequence'
-    __metaclass__ = PoolMeta
 
     periods = fields.One2Many('ir.sequence.period', 'sequence', 'Periods',
         states={'invisible': Eval('type') != 'incremental'},
@@ -44,7 +43,7 @@ class Sequence:
     def get_id(cls, domain, _lock=False):
         if isinstance(domain, cls):
             domain = domain.id
-        if isinstance(domain, (int, long)):
+        if isinstance(domain, int):
             domain = [('id', '=', domain)]
 
         with Transaction().set_context(user=False, _check_access=False):
@@ -115,7 +114,7 @@ class SequencePeriod(ModelSQL, ModelView, MatchMixin):
     @classmethod
     def create(cls, vlist):
         periods = super(SequencePeriod, cls).create(vlist)
-        for period, values in izip(periods, vlist):
+        for period, values in zip(periods, vlist):
             if sql_sequence and not cls._strict:
                 period.update_sql_sequence(values.get('number_next',
                         cls.default_number_next()))
@@ -226,9 +225,8 @@ class SequencePeriod(ModelSQL, ModelView, MatchMixin):
         return self.start_date <= date <= self.end_date
 
 
-class SequenceStrict:
+class SequenceStrict(metaclass=PoolMeta):
     __name__ = 'ir.sequence.strict'
-    __metaclass__ = PoolMeta
 
     # needed due to both models share form view
     periods = fields.Function(
diff --git a/purchase.py b/purchase.py
index 5b239c1..6264a4f 100644
--- a/purchase.py
+++ b/purchase.py
@@ -7,9 +7,8 @@ from trytond.transaction import Transaction
 __all__ = ['Purchase']
 
 
-class Purchase:
+class Purchase(metaclass=PoolMeta):
     __name__ = 'purchase.purchase'
-    __metaclass__ = PoolMeta
 
     @classmethod
     def __setup__(cls):
diff --git a/sale.py b/sale.py
index 0c74633..9264495 100644
--- a/sale.py
+++ b/sale.py
@@ -7,9 +7,8 @@ from trytond.transaction import Transaction
 __all__ = ['Sale']
 
 
-class Sale:
+class Sale(metaclass=PoolMeta):
     __name__ = 'sale.sale'
-    __metaclass__ = PoolMeta
 
     @classmethod
     def __setup__(cls):
diff --git a/setup.py b/setup.py
index 5ae08a5..978af2d 100644
--- a/setup.py
+++ b/setup.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # The COPYRIGHT file at the top level of this repository contains
 # the full copyright notices and license terms.
 
@@ -6,10 +6,7 @@ from setuptools import setup, find_packages
 import re
 import os
 import io
-try:
-    from configparser import ConfigParser
-except ImportError:
-    from ConfigParser import ConfigParser
+from configparser import ConfigParser
 
 MODULE2PREFIX = {}
 
@@ -19,6 +16,7 @@ def read(fname):
         os.path.join(os.path.dirname(__file__), fname),
         'r', encoding='utf-8').read()
 
+
 def get_require_version(name):
     if minor_version % 2:
         require = '%s >= %s.%s.dev0, < %s.%s'
@@ -28,6 +26,7 @@ def get_require_version(name):
         major_version, minor_version + 1)
     return require
 
+
 config = ConfigParser()
 config.readfp(open('tryton.cfg'))
 info = dict(config.items('tryton'))
@@ -45,7 +44,9 @@ requires = []
 for dep in info.get('depends', []):
     if not re.match(r'(ir|res)(\W|$)', dep):
         prefix = MODULE2PREFIX.get(dep, 'trytond')
+
         requires.append(get_require_version('%s_%s' % (prefix, dep)))
+
 requires.append(get_require_version('trytond'))
 
 tests_require = []
@@ -99,15 +100,16 @@ setup(name=name,
         'Natural Language :: Slovenian',
         'Natural Language :: Spanish',
         'Operating System :: OS Independent',
-        'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: Implementation :: CPython',
         'Programming Language :: Python :: Implementation :: PyPy',
         'Topic :: Office/Business',
         ],
     license='GPL-3',
+    python_requires='>=3.4',
     install_requires=requires,
     dependency_links=dependency_links,
     zip_safe=False,
@@ -118,5 +120,4 @@ setup(name=name,
     test_suite='tests',
     test_loader='trytond.test_loader:Loader',
     tests_require=tests_require,
-    use_2to3=True,
     )
diff --git a/stock.py b/stock.py
index f538b6c..06959f9 100644
--- a/stock.py
+++ b/stock.py
@@ -21,26 +21,21 @@ class ShipmentMixin(object):
         return res
 
 
-class ShipmentOut(ShipmentMixin):
+class ShipmentOut(ShipmentMixin, metaclass=PoolMeta):
     __name__ = 'stock.shipment.out'
-    __metaclass__ = PoolMeta
 
 
-class ShipmentOutReturn(ShipmentMixin):
+class ShipmentOutReturn(ShipmentMixin, metaclass=PoolMeta):
     __name__ = 'stock.shipment.out.return'
-    __metaclass__ = PoolMeta
 
 
-class ShipmentIn(ShipmentMixin):
+class ShipmentIn(ShipmentMixin, metaclass=PoolMeta):
     __name__ = 'stock.shipment.in'
-    __metaclass__ = PoolMeta
 
 
-class ShipmentInReturn(ShipmentMixin):
+class ShipmentInReturn(ShipmentMixin, metaclass=PoolMeta):
     __name__ = 'stock.shipment.in.return'
-    __metaclass__ = PoolMeta
 
 
-class ShipmentInternal(ShipmentMixin):
+class ShipmentInternal(ShipmentMixin, metaclass=PoolMeta):
     __name__ = 'stock.shipment.internal'
-    __metaclass__ = PoolMeta
diff --git a/tox.ini b/tox.ini
index 32f9ac1..8c73716 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,18 +1,15 @@
 [tox]
-envlist = {py27,py36}-{sqlite,postgresql,mysql},pypy-{sqlite,postgresql}
+envlist = {py36,py37}-{sqlite,postgresql},pypy3-{sqlite,postgresql}
 
 [testenv]
 commands = {envpython} setup.py test
 deps =
-    {py27,py36}-postgresql: psycopg2 >= 2.5
-    pypy-postgresql: psycopg2cffi >= 2.5
-    mysql: MySQL-python
-    sqlite: sqlitebck
+    {py36,py37}-postgresql: psycopg2 >= 2.5
+    pypy3-postgresql: psycopg2cffi >= 2.5
+    {py36}-sqlite: sqlitebck
 setenv =
     sqlite: TRYTOND_DATABASE_URI={env:SQLITE_URI:sqlite://}
     postgresql: TRYTOND_DATABASE_URI={env:POSTGRESQL_URI:postgresql://}
-    mysql: TRYTOND_DATABASE_URI={env:MYSQL_URI:mysql://}
     sqlite: DB_NAME={env:SQLITE_NAME::memory:}
     postgresql: DB_NAME={env:POSTGRESQL_NAME:test}
-    mysql: DB_NAME={env:MYSQL_NAME:test}
-install_command = pip install --pre --process-dependency-links {opts} {packages}
+install_command = pip install --pre {opts} {packages}
\ No newline at end of file
diff --git a/tryton.cfg b/tryton.cfg
index 0426b97..738e2be 100644
--- a/tryton.cfg
+++ b/tryton.cfg
@@ -1,5 +1,5 @@
 [tryton]
-version=4.8.0
+version=5.0.0
 depends:
     ir
     res