Considering upgrade of CMS to latest version- the process may take anywhere from 2 to 4 weeks.
May suggest - we need to work on live server, what we have planned:
take exact replica of site and move to a test domain, but on live server
Block Google, Bing, Yahoo -
User-agent: Google Disallow: /,
User-agent: Bing Disallow: /,
User-agent: Yahoo Disallow: /in robots.txt
Will upgrade CMS and add functionality - will test the entire structure, check URLusing xenu and move on to configure the site on original domain
The process upgradation and new tools may take 2 to 4 weeks....
Concern is that despite blocking Google, Bing & Yahoo through
User agent disallow
can still the URLof test site can be crawled by the search engines - if yes - it may hurt the original site as will read on as entire duplicate or is there any alternate way around.