Because the date of August 1 is so important. It is the deadline for the activation of segwit, which is the next step in the Bitcoin Network Scaling, is an update in the software that miners use as independent nodes.
It is advisable that before this date stop receiving or sending bitcoins because you run the risk that some of the transactions are not registered in the chains to be established, make sure you have all your coins in portfolios in which you control the private keys Or a hardware wallet to keep your coins safe in these times of transition. We do not know exactly which exchange houses will accept the new chain and we run the risk that transactions will be in shorter chains that will not prevail, will see little supply and it is possible that there is extreme volatility in that days, after the event is important Observe to be following the means to know what the news is before any eventuality.