Index: domoticz-2020.2/hardware/plugins/DelayedLink.h
===================================================================
--- domoticz-2020.2.orig/hardware/plugins/DelayedLink.h
+++ domoticz-2020.2/hardware/plugins/DelayedLink.h
@@ -14,6 +14,16 @@
 #include <frameobject.h>
 #include "../../main/Helper.h"
 
+#ifndef _Py_DEC_REFTOTAL
+  /* _Py_DEC_REFTOTAL macro has been removed from Python 3.9 by:
+    https://github.com/python/cpython/commit/49932fec62c616ec88da52642339d83ae719e924 */
+#  ifdef Py_REF_DEBUG
+#    define _Py_DEC_REFTOTAL _Py_RefTotal--
+#  else
+#    define _Py_DEC_REFTOTAL
+#  endif
+#endif
+
 #if PY_VERSION_HEX >= 0x030800f0
 static inline void
 py3__Py_DECREF(const char *filename, int lineno, PyObject *op)
Index: domoticz-2020.2/CMakeLists.txt
===================================================================
--- domoticz-2020.2.orig/CMakeLists.txt
+++ domoticz-2020.2/CMakeLists.txt
@@ -744,7 +744,7 @@ else()
   message(STATUS "Not found telldus-core (telldus-core.h), not adding tellstick support")
 endif (TELLDUSCORE_INCLUDE)
 
-target_link_libraries(domoticz ${Boost_LIBRARIES} ${ZLIB_LIBRARIES} ${MINIZIP_LIBRARIES} ${CURL_LIBRARIES} pthread -lpython3.8 -lcrypt -lpthread -ldl -lutil -lm -lm ${MQTT_LIBRARIES} ${LUA_LIBRARIES} ${CMAKE_DL_LIBS} ${TELLDUS_LIBRARIES})
+target_link_libraries(domoticz ${Boost_LIBRARIES} ${ZLIB_LIBRARIES} ${MINIZIP_LIBRARIES} ${CURL_LIBRARIES} pthread -lpython3.9 -lcrypt -lpthread -ldl -lutil -lm -lm ${MQTT_LIBRARIES} ${LUA_LIBRARIES} ${CMAKE_DL_LIBS} ${TELLDUS_LIBRARIES})
 
 IF(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
   target_link_libraries(domoticz -lresolv)