Update 0.3.4 to 0.5.5

Hi,

I am testing the update with a copy of my website.
After the update, all my post list have been deleted.
Then I have created an export file (from the oneline version – old version) and try to import it in the new version, but no APL have been created.
I didn’t see any message error.

Could you give me a process to update the version ?

Thanks