Originally, it was expected that the new operating system would be released in February for those who have the older Lumia handsets, although there had been plans for upgrades to be carried out in December. However, the company is reported to have announced to its partners that the rollout would take place this month. The aim is to have the update happen after the monthly service updates take place for the Lumia handsets that already have Windows 10 installed. Users of the Lumia 950 and 950 XL are already using the operating system.
However, the new schedule for the release keeps the upgrade as a separate event from the regular service update. Had the upgrade taken place in February it would have been part of the standard update as stated
As the rollout begins, the users will need to start the process from their handsets. Later on, Microsoft is set to begin actively promoting the new operating system to devices that are compatible. Work is continuing on the new handset and users can expect further announcements from the company.
However, industry experts are warning that not all of those who have a handset with Windows Phone 8.1 on it will be able to upgrade immediately. Microsoft has already stated that the upgrades will need to have both manufacturer and carrier approval and in some cases this could take a while to achieve.