In his latest post over on the SitePoint PHP Blog today, Harry Fuecks has his look at the hows and whys of shared hosts upgrading to PHP5.

For me, wearing a “shared host customer” hat, the number 1 issue is information—if a host want’s to migrate to PHP5, they need to communicate a clear schedule for doing so, with realistic time frames (e.g. at least 3 months warning). With that should be the warning that customers need to start testing their code against the new PHP version.

To that extent think shared hosts need to release full details here—the exact PHP 5 version they plan to use, a sample php.ini reflecting how PHP will be configured, a list of extensions which will be available and anything else that might be relevant.

He also suggests that a host provide a place for users to test their code (think sandbox), or provide them with a "ready to install" version of what the host will ultimately configure...