Since 2018, many technological developments have been carried out by IFREMER and its partners, in particular LIRMM, first as part of the pIOT project and then the IOT project. Thus between version 0 and version 2 under development, the weight of the tags has been reduced from more than 100 g to less than 20 g, their size from 9x7x3cm to 5.5x3.5x1.7cm. The size of the battery has also decreased considerably, the number of sensors has increased even though the size of the electronic board was halved. Version 2 of the tag will include an external antenna as well as an internal antenna to overcome the problems of breaking the external antenna against coral or rocks. The composition of the box will be of better quality and a version 2.2 will even accommodate a small solar panel on the top of the tag.