Note that the versions are also in README.txt.

Doc/Makefile

@@ -29,6 +29,7 @@ help:
 	@echo "  dist      to create a \"dist\" directory with archived docs for download"
 
 checkout:
+	# Note: if you update versions here, do the same in README.txt
 	@if [ ! -d tools/sphinx ]; then \
 	  echo "Checking out Sphinx..."; \
 	  svn checkout $(SVNROOT)/external/Sphinx-0.6.1/sphinx tools/sphinx; \