diff --git a/doc/release/1.8.0-notes.rst b/doc/release/1.8.0-notes.rst
index 764b968..559ec9e 100644
@@ -29,7 +29,12 @@ pointer to the data was hashed as an integer. Now, the hash function uses
the tuple-hash algorithm to combine the hash functions of the elements of
the scalar, but only if the scalar is read-only.
-Forcing the old, one file per extension build may be enabled by exporting the
+Numpy has switched its build system to using 'separate compilation' by default.
+(In previous releases this was supported, but not default.) This should produce
+the same results as the old system, but if you're trying to do something
+complicated like link numpy statically or using an unusual compiler, then it's
+possible you will encounter problems. If so, please file a bug, and as a
+temporary workaround you can re-enable the old build system by exporting the
shell variable NPY_SEPARATE_COMPILATION=0.