As reported by Censor.NET, he wrote about it in his blog.
"Profound amendments to the Constitution should not be decided on the sidelines of the Parliament or at the talks in the foreign capitals. The people of Ukraine should speak first.
"The only condition for the People's Front faction's vote on the most important issues regarding the Constitution of Ukraine is the people's referendum verdict. No other ways!," Avakov stressed.
He also listed the most important issues of the Constitutional referendum:
1. Ukraine's integrity, statuses of separate territories (?);
2. Real judicial reform with renewal of all courts and judges;
3. Transition to a parliamentary republic and elimination of competition among branches of power;
4. Decentralization as the basis for the unitarian nationhood;
5. Geopolitical direction towards the EU and NATO.