The official Pokémon GO account has just tweeted the following, reminding Trainers to claim their defender bonuses soon:

We’ve already been informed by Niantic’s customer support that there is no fixed timeline for the gym remodelling, as “there is a lot of moving pieces to this change”.

It’s expected that the gyms will be disabled during PDT work hours, roughly 5 hours from now. It’s not known for how long the gyms will be disabled, but it’s expected that the outage will lasts for at least 3-4 hours.

We have tried placing a new Pokémon inside a Gym and claiming the Defender Bonus prior to writing this article. The whole process went without any problems, so we’re now waiting to see what will happen once Gyms get disabled.

It’s not yet known if the Pokémon will return to their Trainers at full health or they will be fainted. It’s also not known if any special medals will be awarded to Pokémon currently in the Gym.

The only thing that we know about this Gym rework is a number of network messages that leaked earlier:

Gym rework notifications
Notification Variant
Nearby raid is starting   There’s a raid about to start near you!
A raid’s going to start nearby!
Nearby raid starting soon!
Pokémon won a battle   {0} defended the Gym!
{0} was victorious in battle!
{0} has triumphed over your opponents!
Pokémon lost a battle   {0} lost a battle!
{0} was defeated in battle!
{0} fainted at the Gym!
Gym removal   {0} has fought hard and returned!
{0} is back after a hard battle!
{0} was forced off the Gym!
Pokémon is hungry   {0} is hungry!
{0} needs a pick-me-up!
{0} wants a berry!