[Zope] when can a product be refreshed?

[robert]

martin f krafft wrote:

>also sprach robert <robert at redcor.ch> [2005.02.02.2323 +0100]:
>  
>
>>And there are products that can not be refreshes.
>>Restarting Zope is then the only solution
>>    
>>
>
>What determines whether a product can be refreshed?
>  
>
It needs to have a refresh.txt file in its folder. The file can be 
empty. Only its existence is tested.
Some products can not be refreshed for "internal" reasons. To my 
knowledge this is the case, when a product  imports libraries as part 
one of its methods.

Robert