Earlier this year we announced that we were undertaking an effort to reprocess campaigns 0–14 using the same version of the Kepler/K2 pipeline used for C15 and subsequent campaigns. This version introduced several new features and improvements, such as more sophisticated pixel calibration, better identification of spacecraft pointing, improved cosmic ray correction, and production of short-cadence lightcurves, along with several other minor improvements. Please see the associated news post for details on each feature.
Reprocessed data and release notes from campaign 0 are now available --- 2, 3, and 13 were made available over the past few months. The newest data are available via the usual K2 data download interfaces at the MAST archive; the older data has been kept available via the MAST browser interface (e.g., here for tarballs of the old target pixel files (TPFs) and here for tarballs of the old lightcurve files, if previously produced). The data release notes have been updated for each reprocessed campaign, available at the nominal K2 Data Release Notes page; links to the old version of the release notes are also provided for posterity.
Given the unique features of C0 compared to most K2 campaigns, and the significant updates made to the K2 pipeline since the last C0 data release, we highly encourage users to read the updated C0 Data Release Notes.
The next reprocessed campaign to be delivered will be C11, followed by C1 — see this post for the expected processing order of additional campaigns. (Note that the reprocessing activity does not impact the regular deliveries of newly obtained data, e.g., C19, currently expected in early February.)