The legal dispute is whether there exists a legal obligation to update the ECDIS application software for vessels relying on ECDIS as the primary means of navigation. The following is a condensed exposé of the legal dispute: SOLAS Chapter V/27 establishes that ‘nautical charts […] shall be adequate and up to date’, but gives no further details as to what ‘up-to-date’ means for ENC’s and for paper charts. A strict interpretation of this provision would be that only the ENC’s themselves have to be updated – an action which is similar with the replacement of paper charts with up-to-date ones. However, the authority of this strict interpretation is quickly eroded when the following aspect is taken into account: if the ECDIS machine is running an older application software, the up-to-date ENC’s may be displayed with errors. As learned from several surveys which are referred to later in this work, there could be many different types of errors, each with a different degree of seriousness – for instance, newer features like Particularly Sensitive Areas (PSSA) and Archipelagic Sea Lanes (ASL) may not be displayed at all by ECDIS machines running older application software. In trying to combat this growing phenomenon, the IMO has adopted performance standards for ECDIS systems, most recently through Resolution MSC.232(82) from 2006. These performance standards were made mandatory by direct reference in SOLAS V/18.4. Further, the IMO has adopted two (non-mandatory) guidance circulars, in an attempt to further clarify the requirements for maintenance of ECDIS software: IMO SN.1/Circ.266/Rev.1 (2010) and IMO MSC.1/Circ.1503 (2015). The latter instrument, for instance, states that ‘[…] ECDIS software should be kept up to date such that it is capable of displaying up-to-date electronic charts correctly according to the latest version of IHO's chart content and display standards.’ The issue is that although the language used in the latter circular is very strong, the instrument itself is a mere guidance and hence not legally binding – unless it is voluntarily made mandatory by Flag Administrations. For this reason, it cannot simply be concluded that ‘up-to-date navigational charts’ (as per SOLAS V/27) implies that the ECDIS software has to be updated as well in order to correctly display the ENC’s, because such an interpretation would clash with the requirement in SOLAS V/18.4. From this provision it seems that an ECDIS having a valid type approval certificate at the date of installation will continue to comply with the carriage requirement of regulation SOLAS V/220.127.116.11 also when the relevant ECDIS software is updated afterwards. To put it more simply, this means that even in the absence of any software update for the entire life of the vessel, the ECDIS would still comply with SOLAS. Of course, since vessels have a rather long life-cycle, and computer technology has seen a sharp increase in the last two decades (trend which is likely to continue at an exponential rate), one can reasonably expect the hardware – let alone the software – installed when the vessel was launched to become obsolete well before the vessel is taken out of service. Having set the background of the legal dispute, the legal question that this dissertation will seek to answer is: in the international legal framework as it stands today, is there an unambiguous obligation to update the ECDIS software in order to correctly display the up-to-date ENC’s? The research question will be answered in Chapter 1. Upon answering the main research question, Chapter 2 will discuss the differences between integrated and non-integrated ENC updates. In the end, Chapter 3 will conclude this dissertation by attempting to portray the lex ferenda – focusing primarily on whether such an unambiguous obligation to update the ECDIS software should exist from the point of view of safety of navigation.