I can't find a 1.4sr3 to 1.4sr4 upgrade in the downloads section. Is the 1.4sr4 to 1.4sr5 download sufficient? If so, how about changing the file description to say it upgrades both versions? If not, where's the missing fix?
As explained in the release announcement, the upgrade to 1.4.0sr4 actually requires you to remove something, so it doesn't make a lot of sense to provide an upgrade archive.
Do these steps manually, then install the 1.4.0sr5 update.