Swift/XRT (light blue diamonds) and Swift/BAT (light grey open circles) light curves during and after the 2015/2016 type II outburst of 4U 0115+63 and the Swift/XRT (red stars) and Swift/BAT (black circles) light curves during the 2017/2018 campaign for the source. In the top panel, we show the light curves obtained during both campaigns but aligned using the start times of these outbursts. The zero-points of the light curves correspond to 2015 October 9 (MJD 57304), and 2017 July 22 (MJD 57956). In the bottom panel, we show the same light curves again but now aligned with respect to the occurrence of the first periastron passages after the type II outbursts (around day 50 in the light curves). Our 2016 and 2018 XMM-Newton observations are shown as a light blue up-pointing triangle and a red square, respectively, and the times at which these observations were obtained are also indicated by the two yellow marks. The XRT and XMM-Newton count rates are calculated in the 0.5−10 keV energy range, while the BAT count rates are shown in the 15−50 keV range. The XMM-Newton count rates have been converted to Swift/XRT count rates (see Sect. 2.1 for more details). Periastron passages for the 2017/2018 data set (computed using the orbital parameters in Raichur & Paul 2010) are indicated by the vertical dotted lines, and the quiescent level of 4U 0115+63 (see Sect. 2.2) is shown by the dashed brown line in the figures. All errors are 1σ.