With plans of the hard fork being enacted this coming week, more exchanges are alerting their users of the changes to commence. To reiterate, if exchanges do not update their software after the hard fork, this could result in transactions being executed on a false chain, thus resulting in financial losses.
Gemini, the first licensed Bitcoin and Ether exchange, has just alerted their users to the halt in an email:
If you intend to deposit or withdraw ether on Gemini in the next week, please continue reading below to learn about our updated exchange operations.
Beginning at midnight EDT on Tuesday, July 19, 2016 (Wednesday, July 20 at 04:00 UTC), Gemini will temporarily disable all ether deposits and withdrawals in advance of the forthcoming Ethereum "Hard Fork." For more details on the technology behind this event, please see our recent blog post: Ethereum “Hard Fork”: Modified Exchange Operations.
We will resume allowing ether deposits and withdrawals after the "Hard Fork" has been resolved, which is anticipated to be sometime Thursday, July 21 (EDT). Gemini users may still trade ether on our ETH/USD and ETH/BTC matching engines while ether deposits and withdrawals are temporarily disabled.
If you have any questions, please contact Gemini customer support at firstname.lastname@example.org.
Onward and upward,
Stay tuned to receive more updates on the Gemini halt.