Joomla lower version to higher version

Have uploaded joomla higher version to the existing site which has lower version.. so am getting error

jtablesession::Store Failed DB function failed with error number 1054 Unknown column 'client_id' in 'field list' SQL=INSERT INTO jos_session

any suggetion how t开发者_JS百科o retrive it back or to remove this bug??

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Could you be more specific about versions?

If all changes are within 1.5.x then you can visit http://joomlacode.org/gf/project/joomla/frs/?action=index and find something...

Upgrade from 1.5 to 1.6 is not possible for now. You need to reinstall the system

1.0.x->1.5.x: http://docs.joomla.org/Migrating_from_1.0.x_to_1.5_Stable