Reverting to older WP Version

Hi, I am after advice on a tricky situation. I am thinking of reverting to a previous version of WP 3.4.2 for a site with a plugin that is not 3.5.1 compliant, but I need it and can’t get a replacement. Not an ideal situation I know, but am wondering if the better security plugin would be a fix (not a garauntee) for security issues that may arise if I revert to 3.4.2. The site is a small mamas and papas level site, so am not expecting direct attacks, although I’m guessing the attack bots don’t differentiate between size of sites? Any help much appreciated, Earl

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