To update Nokia Lumia Software, first of all, you need to install Zune Software onto your PC/Laptop thereafter you can update your Nokia Lumia Software. So first of all, install Zune Software in your PC/Laptop. To install Zune click here if you already have Zune Software in your PC/Laptop then just follow given steps to update Nokia Lumia Software. You cannot update Windows 7.8 phones to Windows 8 because of hardware requirements to install Windows 8 but you can install new updates for your phone if updates are available on Zune Software. Yes if you have Windows 8 phone then you can also install updates if new updates are available on Zune Software. Also you should have an active internet connection to update new installations.
STEP 1: First of all, Download Zune in your PC/Laptop. For that purpose, visit official website of your phone’s app store.
Note : If you already installed Zune then skip step 1 and proceed to next step.
STEP 2: After installing Zune, connect your phone to your PC/Laptop. When you will connect your phone to your PC/Laptop then Zune will automatically open. If Zune does not open automatically then open Zune manually. When Zune will open then Sign In with your Windows Live Id after that go to settings of Zune Software.
STEP 3: Now Click on phone as shown in screenshot and then click on Update. When you will click on update then Zune will start to search new updates for your phone. When searching will finish Zune will show list of updates, if your phone will up to date then Zune will show that your phone is up to date. If there is any update available for your phone then click to install that update.