Actually until SungrowModbusTcpClient is updated I'll just set a max version on pymodbus.

Author: tjhowse

setup.py

@@ -17,9 +17,9 @@
     install_requires=[
         'ruamel.yaml>=0.16.12',
         'paho-mqtt>=1.5.0',
-        'pymodbus>=2.3.0',
+        'pymodbus>=2.3.0,<3.0.0',
         'click>=6.7',
-        'SungrowModbusTcpClient>=0.1.7',
+        'SungrowModbusTcpClient>=0.1.6',
     ],
     tests_require=[
         'nose2>=0.9.2',