# 2.12.12. Upgrading to Buildbot 2.0

Upgrading a Buildbot instance from 1.x to 2.0 may require some work to achieve. The primary changes are removal of deprecated APIs and removal of Python 2.7 support.

The recommended upgrade procedure is as follows:

> - Upgrade to the last released BuildBot version in 1.x series.

> - Remove usage of the deprecated APIs. All usages of deprecated APIs threw a deprecation warning at the point of use. If the code does not emit deprecation warnings, it’s in a good shape in this regard.

> - Upgrade master to Python 3. Note that 1.x series has some bugs in Python 3 support, so any Python-related issues encountered in this step are relatively harmless as they will be fixed after upgrading to 2.0. You may need to run the master on a real workload in order to force all deprecated code paths to be exercised.

> - Upgrade to Buildbot 2.0.

> - (Optional) Upgrade to newest Buildbot 2.x. The newest point release will contain bug fixes and functionality improvements. Note that BuildBot 2.3.0 drops support for Internet Explorer 11 and some other old browsers.