Are they on Crystal 11 (XI) or Crystal 2011 (there's a difference - I suspect it's 2011) Either way, all of your Crystal 10 reports should work with no problem.  The actual format of the .rpt file really hasn't changed and no features have been removed since Crystal 9.  The Crystal XI or 2011 runtimes will run reports created in Crystal 10 and reports created in either of those versions can be opened in Crystal 10 if none of the new features added since Crystal 10 have been used in the report.  However, you will probably want to purchase the correct version of Crystal for modifying existing reports and creating new ones.

this is what our software provider wrote: 

our .Net viewer

> (which is what we will be using on all reports in the future) uses

> components only in Crystal 2011. It could cause you significant

> problems if you have a lot of custom reports. The best solution is to

> update to Crystal

> 2011 and update all of your custom reports to 2011.