Incomplete Blast Database In Ubuntu

hello all, i am trying to do local blast using this command

 blastall -p blastn -n T -i query.fasta -d nt.12 -o /blast.out

i am doing a "blastn" , "-n T" shows i want to megablast. i have downloaded database "nt.12' from NCBI website.(assuming that its latest). but when i run this command i get a different result than the result i get when i do this blast at NCBI with default settings.

i noticed that blast version on my computer is "BLASTN 2.2.21 [Jun-14-2009]" but on the NCBI site its "BLASTN 2.2.27" so i think the problem lies with version of blast.

can anyone guide me to update my blast version to "BLASTN 2.2.27" or anyone thinks its a different problem.

thanks