With the shortening of the Phase III implementation period, a number of lines (Lines 16 and 12) planned in 2007's Phase III moved into the next phase. By 2016, it was determined that Phase IV will have an implementation period between 2017 and 2022 and consist of 274 km of new subway. Lines 13 and 14 which originally had a long term 2030 completion deadline were moved into Phase IV expansion. In addition, a branch line of Line 6 will connect with the neighboring Dongguan Rail Transit system. Lines 12, 13, 14, and 16 and branch of Line 6 started construction in January 2018. Line 12, 13, 14, 16, and the branch of Line 6 was approved by the NDRC in July 2017. The first phase of Line 20 was fast tracked from Phase IV to provide a shuttle between Line 11 and a new International Convention Center. The construction started in September 2016, but as for early 2019, the construction is paused because the Development and Reform Commission did not approve the project.