Hi Sebastien,
  On 25 Apr 2017, at 13:02, Sebastian Luna Valero
<sebastian.luna.valero(a)gmail.com> wrote:
 Hi All,
 Thanks for releasing XWiki 8.4.5!
 I am about to import content from the old to the new xwiki, 
You should really consider using the recommended upgrade practice which is to use the
Distribution Wizard, see 
http://platform.xwiki.org/xwiki/bin/view/AdminGuide/Upgrade
If you really want to import content make sure you don’t include any default page at
least. I’d still recommend using the DW.
Thanks
-Vincent
  but the .xar
 file is larger than the 32MB size limit. Previously I have followed the
 instructions here:
 
http://platform.xwiki.org/xwiki/bin/view/AdminGuide/Attachments
 to increase the maximum size of the attachment. However, it seems to work
 only for the main wiki but not for subwikis, is that true?
 Best regards,
 Sebastian