Using Web of Science and Unpaywall data, we here provide an update of Open Access (OA) levels of Dutch universities, for 2016 and 2017. Our previous analysis (10.5281/zenodo.1133759 and 10.7287/peerj.preprints.3520v1) looked at OA classification as included in Web of Science (gold and green OA, based on Unpaywall data), and supplemented that with a breakdown of gold OA into pure gold, hybrid and bronze, taken from Unpaywall data (formerly OADOI) directly. Here, we improve on this by running all DOIs retrieved from WoS through Unpaywall data (using their web interface that allows batch checking of up to 10,000 DOIs at a time). Unlike WoS, Unpaywall data itself includes author-submitted versions in their green OA classification, resulting in more complete green OA levels. In addition, since our initial analysis of December 2017, Unpaywall data has considerably expanded its coverage of institutional repositories (IRs) (see https://unpaywall.org/sources). This now includes coverage of the IRs from all Dutch universities. Taken together, the current data show higher levels of green open access, including author-submitted versions, compared to our previous analysis. In this update, we include output (articles and reviews) from 2016 and 2017 for all 14 universities in the Netherlands. The following categories are distinguished (description taken from Piwowar at al., 2018, doi:10.7717/peerj.4375) Pure gold: Published in an open-access journal (as defined by the DOAJ) Hybrid: Free under an open license in a toll-access journal Bronze: Free to read on the publisher page, but without a license Green: Available from an institutional or disciplinary repository (including PubMedCentral) Data for Dutch universities were collected from Web of Science using the organization-enhanced field. Only articles and reviews were included. DOIs were extracted from the Web of Science export, run through the Unpaywall data Simple Query Tool. From the resulting data from Unpaywall, OA classification was done using a simple formula in Excel ...