If I use the "updates" repository, do I still need the "security" repository?

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http://askubuntu.com – For the limited number of package I looked at (e.g. apache), I found that the package version in the updates repository is always newer than or equal to the version available in the security repository (provided that they exist). This gives me the impression that all security patches posted to the security repository are also posted to the updates repository. If this is true, I can remove all <release_name>-security entries in my apt sources.list and the <release_name>-updates entries will still give me the security patches. This will speed up apt-get update quite a bit. The best (HowTos)