13: Tokyo, Japan on 21 December 2013. Aerts was initially expected to compete in a heavyweight tournament at GFC Series 1 in Dubai, United Arab Emirates on 29 May 2014. However, a press statement issued by the promotion later stated that he would fight on the card in a one-off fight against Dewey Cooper. Aerts fought to a draw with Cooper, tearing his hamstring during the match. Aerts fought Freddy Kemayo at Fight Night Saint-Tropez II in Saint-Tropez, France on 4 August 2014, losing by TKO as a result of a leg injury in round two. He then faced Ernesto Hoost for the sixth time on 19 October 2014 in Osaka for the vacant WKO World Heavyweight Championship. The 49-year-old Hoost won by unanimous decision after three, two-minute rounds. In June 2015, Aerts – at 44 years old – officially announced his retirement via video at a press conference for an upcoming kickboxing show in Japan that he was scheduled to appear on. Aerts noted that he had sustained some injuries in his October fight with Ernesto Hoost, and when he was unable to fully recover from those injuries, he made the decision to retire. Aerts' retirement was short-lived, however, and he returned to the ring to compete in his third mixed martial arts match, against the debuting Estonian sumo wrestler Baruto Kaito at Rizin World Grand Prix 2015: Part 2 at the Saitama Super Arena on 31 December 2015. He lost to his larger opponent via a lopsided unanimous decision. In yet another retirement match, Aerts was scheduled to face Tsotne Rogava at WFL 5: Champion vs. Champion in Almere on 23 April 2017, but his opponent was later changed to Nordine Mahieddine. Aerts defeated Mahieddine by unanimous decision to record his 105th career win. Afterwards, he was joined in the ring by fellow Dutch kickboxing legends Ernesto Hoost, Remy Bonjaskyn and Semmy Schilt, who were on hand to congratulate the retiring Aerts. Aerts took part in a scoreless exhibition bout against Atakan Arslan at MFC 24 in İzmir, Turkey on 27 January 2018. On 26 July 2018, Aerts lost by unanimous decision to Jan Soukup at Yangames Fight Night 6 in Prague, Czech Republic. He defeated Christian Müller via KO due to a knee strike in the first round of their match at La Familia Fight Night X in Halle, Germany on 4 May 2019. The 49-year-old Aerts