diff --git a/Include/pystate.h b/Include/pystate.h
index afc3c0c..6ca463f 100644
--- a/Include/pystate.h
+++ b/Include/pystate.h
@@ -51,6 +51,16 @@
 } PyInterpreterState;
 #endif
 
+typedef struct _co_extra_state {
+    struct _co_extra_state *next;
+    PyInterpreterState* interp;
+
+    Py_ssize_t co_extra_user_count;
+    freefunc co_extra_freefuncs[MAX_CO_EXTRA_USERS];
+} __PyCodeExtraState;
+
+/* This is temporary for backwards compat in 3.6 and will be removed in 3.7 */
+__PyCodeExtraState* __PyCodeExtraState_Get();
 
 /* State unique per thread */
 
@@ -142,8 +152,10 @@
     PyObject *coroutine_wrapper;
     int in_coroutine_wrapper;
 
-    Py_ssize_t co_extra_user_count;
-    freefunc co_extra_freefuncs[MAX_CO_EXTRA_USERS];
+    /* Now used from PyInterpreterState, kept here for ABI
+       compatibility with PyThreadState */
+    Py_ssize_t _preserve_36_ABI_1;
+    freefunc _preserve_36_ABI_2[MAX_CO_EXTRA_USERS];
 
     PyObject *async_gen_firstiter;
     PyObject *async_gen_finalizer;