Preq packet ->
if (session.character.level < 20 && packet.destmapinstance.mapid == 1)
{
session.sendpacket(session.generatemsg("gneugneu", 0));
return;
}
then you can't access to the map without reaching a specific level or
GenerateMonsterBonus ->
Search for GenerateXp ->
if (session.character.level < 20 && session.currentmapinstance.mapid == 1)
{
GenerateXp();
}
then no more xp
both ways are not clean but still do the work