SUSS4.1 is a new 2018 release of the XMM OM Serendipitous Ultraviolet Source Survey catalogue. This new release corrects some inconsistencies between IAUNAME and SRCNUM found in the previous release (OM SUSS4). The catalogue was compiled for the Optical Monitor instrument on board the ESA XMM Newton observatory. This version, the 4th release of the catalogue, spans the period of observations from 2000 to July 2017. A detailed description of the Catalogue can be found at https://www.ucl.ac.uk/mssl/research-projects/2018/dec/xmm-newton. A refereed paper on the first version can be found in Page M.J. et al. (2012MNRAS.426..903P). In addition to covering a larger observation period, the fourth release differs from the previous one in the implementation of a new time dependent sensitivity degradation correction. As in the previous release, sources detected on stacked images are properly flagged. All data have been fully processed at the European Space Astronomy Centre (ESAC, Madrid, Spain) by using the XMM Science Analysis Software (SAS) system version 17.0. The number of observations (OBSIDs) included in the catalogue is 9,749. The total number of entries in this release is 8,176,156. They correspond to 5,503,765 sources, of which 1,035,453 have multiple entries in the source table, corresponding to different observations. The Catalogue consists of two tables. The first one (SRCLIST) contains the sources, with positional and photometric data (count rate, magnitude and flux) and quality flags for each measurement. In the second table (SUMMARY) we give a summary of the observations from which the sources have been detected and measured.