unable to set dateboosting in apachesolr with D6
For the legacy date field that the ds_ dynamic field is set to use in the 1.6 version schmea.xml, you can use the rord() function. It's not considered best practice any longer but it works with field types that don't enable using ms(). More information at Solr Wiki. The example query goes like this (copying it here to avoid link rot):

recip(rord(creationDate),1,1000,1000)