How to trigger a block update in Minecraft 1.9?

Solution 1:

You can trigger block updates in two ways:

1. With player manipulated objects.
2. With non-player manipulated objects.

You would want to use non-player objects so that the player won't even know there was an update needed.

Here is what you should do:

• Let's say your block needs to be updated so it can interact with nearby blocks (command blocks redstone extra).
• You should not use /setblock to place the block as it will not have any redstone mcmeta. Instead, you should use FallingSand. Execute /summon FallingSand <X> <Y> <Z> {Block:<Your Block Here>,Time:1,Data:<Your Damage Value>,TileEntityData:{<Data Like Command Block Commands>}}. This will summon FallingSand entity that updates when it hits the ground.
• If a solid block is not available under your block, then place your block with setblock, then set another block on top or bottom of it and break it by setting an air block in its place. Make sure the air block has the destroy handling for best results. If you use a block to update it, you should use water as it doesn't drop anything when destroyed.
• Other alternatives are:
  • Place string on top and walk over it.
  • Run water across it.