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To find out the release/update dates for a Nucleotide sequence record (for example CP004440.2), access its revision history by changing the display —top left above the record—  from the default GenBank format to Revision History. If you are dealing with patent or intellectual property issues, contact us to confirm the release date of a GenBank record and include the accession number(s) of interest in your message.

The CP004440.2 revision history indicates that the record was released on February 23, 2015. The record was updated twice, but the first update (on April 9, 2015) did not change the sequence, so the version in the accession of the record remained at 1. The submitter updated the sequence on March 16, 2016, which changed the accession version number from 1 to 2.

To see the difference between the CP004440.1 and CP004440.2 sequence, on the revision history report select any two sequences and click the Compare button. Alternatively, you can enter one of the accessions as a Query and the other as a Subject in the Align two sequences BLAST suite, perform your search, and check the alignment.