Referees In December 2016,
PSSI and the league operator planned to use foreign referees for the 2017 competition. The use of foreign referee was intended to improve the quality of the competition. However, two weeks before the league starts, this plan was cancelled. After a wide criticism, protest and dissatisfaction towards the local referees during the first round of the season, PSSI revisited the idea. On 18 July 2017, PSSI and the league operator officially announced the use of foreign referees and assistant referees in select matches for the second round. There were two sets of officials (consisted of 1 referee and 2 assistant referees), each coming from
Australia,
Kyrgyzstan,
Iran, and
Japan.
Player regulation League operator also introduced several new regulations, such as requiring clubs to contract a minimum of five U-23 local players with three of them having to play as starting lineup minimum of 45 minutes in a match, restricting clubs to have more than two players older than 35 years old, and increasing the maximum number of substitutions to five for each team in a match. On 30 July 2017, in preparation for the
2017 Southeast Asian Games, all regulations concerning under-23 players were suspended. Later on 31 August 2017, PSSI decided to extend the suspension of all regulations concerning under-23 players until end of season.
Substitution rule FIFA approved the five substitution rule on 12 April 2017. However, the two additional substitutions (in addition of three substitutions, in accordance to
FIFA Laws of the Game) were only allowed for U-23 players. == Teams ==