# Upgrading pythonwhois

<< back to index
Depending on the version, upgrading to a new version of pythonwhois may entail a need for code changes. These are the usual guidelines:

Major version (x.0.0)
  Major changes have been made to the API. This will almost certainly require a code change.

Minor version (0.x.0)
  Some changes have been made to the API, but these are backwards-compatible. There are probably new features that you're not yet utilizing, but current code will remain functional.

Patch version (0.0.x)
  Minor changes have been made that do not affect the API. Patch releases are usually changes in the parsing or normalization, or support for new WHOIS servers.

More specific instructions are below.

## Upgrading from 1.x to 2.x

The pythonwhois.whois method has been removed, and is replaced by the pythonwhois.get_whois method, which has a significantly different API. The following important changes have to be taken into account:

- Empty keys are no longer filled with nulls; they are now simply absent. You cannot assume anymore that any keys will be present in the response, whatsoever.
- The name_servers key has been renamed to nameservers.
- A new contactskey has been added. Refer to the usage instructions for more information.