30. The Chair and the secretary of the HDH group introduced GRPE-68-14 on the HDH work progress. The HDH Chair summarized the fifteenth and sixteenth group meetings. Having explained the status of validation test programmes, he announced that the validation expected to be completed by the end of March 2014. Following an overview of the remaining open issues, having confirmed that the official submission of the text amending UN GTR No. 4 is expected for June 2014 session of GRPE and having expressed his confidence about the possibility to meet this deadline, he announced that there is a risk of not being able to do so if the validation fails, or if the open issues not solved to the satisfaction of the group. In this case, an extension of the HDH informal working group mandate will be requested at the June 2014 GRPE session.