Lucene migrate to 6.6.5 from 5.5.3

[brahmam]

Hi Team,

we want to migrate from lucene 5.5.3 to 6.6.5.
We see after upgraded to 6.6.5 we are not able to search the existing
data(which was managed with 5.5.3), are we missing anything here during
upgrade?

-- 
Thanks & Regards,
Sree