Egypt's 76 million mobile phone users can expect a temporary blip in services Thursday morning when caller numbers are revised in a drive to meet surging demand.
The changes, due to take place in the early hours of 6 October, will make every Egyptian mobile phone number 11 digits in length.
The National Telecom Regulatory Authority (NTRA) has warned of a potential disruption to all mobile services between the hours of 3am and 6am, lasting anywhere from 30 minutes to 3 hours.
Existing numbers will continue to work for at least four months, with callers receiving a recorded message advising them to update the number before the call is connected.
Amr Badawi, president of the NTRA, told Ahram Online: "We will be monitoring the situation. When we see people have changed to the new system we will announce the old numbers will be discontinued."
Egypt's three mobile operators -- Mobinil, Etisalat and Vodafone -- have launched concerted media campaigns to alert customers and suggest ways to revise their contacts.
Many phone users will be able to download a free application from their network that will automatically update the numbers in their phone address book.
It will also be possible to download these apps from the mobile companies' websites, following links posted on their Facebook and Twitter pages. Many volunteer programmers have also written their own software which can be found online.
These moves seems geared towards smartphone users, but in theory any phone capable of running Java software will be able to utilise the number-updating software.
Nevertheless, mobile firms are expecting the majority of users -- some 60 to 70 per cent -- to use less advanced methods.
Customers will be able to visit network stores, where staff will be able to install the software or manually change the numbers, while local dealers in more remote areas will be able to do the same for a fee, said mobile operator sources.
In June, government figures estimated the number of Egyptian mobile phone users at 76.43 million.
The changes to mobile numbers were announced last Thursday.
Adjustments are as follows:
Current 10 digit numbers, which all start 01, will take an extra 1. They will now begin 011
Current 11 digit numbers, which all start 0152, will change the 5 to a 1. They will now begin 0112
Current 10 digit numbers, which start 01, will add a 2. They will now begin 012
Current 11 digit numbers, which start 0150, will replace the 5 with a 2. They will begin 0120
Current 10 digit numbers, which start 01, will add a 0. They will now start 010
Current 11 digit numbers, which start 0151, will replace 5 with 0. They will start 0101