If there have been no previous protocol changes, Bitcoin will stop on February 7, 2106 at 06:28:15 UTC. This is explained by Bitcoiner educator and author Loïc Morel in the following publication:
Morrell pointed out that each Bitcoin block contains a timestamp (a record of the exact moment it was mined), which acts as a regulator and allows users to: Network nodes verify the chronological order of blocks We will adjust the mining difficulty every two weeks. These marks are stored in unsigned 32-bit fields that measure the number of seconds since January 1, 1970, a standard system of computing known as Unix time.
The problem, Morel said, is that there is a mathematical upper limit because the maximum value that can be stored in a 32-bit field is 4,294,967,295 seconds. Equivalent to February 7, 2106.
Once it reaches 4,294,967,295 seconds, the counter can no longer increase. Morrell likens this to an old car odometer that goes back to zero when it reaches its limit. The problem is not that the car breaks down, but that the counter no longer reflects reality.
Why is this paralyzing Bitcoin?
Morel details: The protocol imposes two rules on timestamps To consider each block as valid:
The first rule states that the new block’s timestamp must be greater than the median of the previous 11 blocks, a value called the median past time (MTP).
The second rule requires that timestamps must not exceed the network’s central time plus two hours to prevent miners from manipulating future clocks. The problem occurs when the MTP reaches its maximum value. At that point, the new timestamp will always be less than or equal to that upper limit, thus violating the first rule requiring a strictly higher value. There are no valid numbers.
According to Morel’s analysis, node rejects new block This is because no one can satisfy both rules at the same time, and the chain stops completely.
Two possible solutions, same failure
Morel describes two technical ways to avoid that scenario. The first is extending the timestamp field from 32 bits to 64 bits. This extends the limit to about 585 billion years. That’s the cleanest solution, says the author. However, all nodes in the network must be updated at the same time.
The second option is called BitBlend and is based on an idea from developer Pieter Wuille, Morrell explains. The 32 bits in the block header are preserved, but interpret them as the visible part of a 64-bit number.
If the timestamp drops sharply relative to the MTP (an indication that the counter has flipped), the node detects the overflow and automatically compensates. This allows for gradual upgrades. Nodes that do not migrate immediately will follow the correct chain until the first overflow in 2106. While this provides temporary backward compatibility, Morell clarifies that it is technically still a hard fork.
In Bitcoin’s history, coordinating this type of exchange has proven politically complex and requires consensus among developers, miners, and node operators. Morel says the technical fix is simple. The real challenge is governance. “We still have 80 years to act,” he concluded.
