diff --git a/docs/INTERNALS b/docs/INTERNALS
index c7308671c..f965ec516 100644
--- a/docs/INTERNALS
+++ b/docs/INTERNALS
@@ -68,7 +68,7 @@ Portability
  GNU Autoconf 2.57
  GNU Automake 1.7 (we currently avoid 1.10 due to Solaris-related bugs)
  GNU M4       1.4
- perl         4
+ perl         5.004
  roffit       0.5
  groff        ? (any version that supports "groff -Tps -man [in] [out]")
  ps2pdf (gs)  ?