There will be no furhter updates to LR 5.
But you can use the free DNG converter which will convert your nefs to dngs, that can be imported in LR 5.
Be aware that the DNG converter only works on the folder level - you cannot select individual files, but have to select a folder to convert.
Thanks for your reply! Is there a way I can ask for a refund? If I had known this in advance I would have waited with my purchase of LR5 and gone for CC instead !
There is usually a grace period, but nowhere near the five months that passed between you bought LR5 and when LR6 was released.
But you can upgrade to LR6 for 79 US dollars (or equivalent) here: Products
Click on Buy, then choose Upgrade.
Alternatively, you can buy a Creative Cloud Photography Plan subscription, Photoshop and Lightroom for $10 a month.
The subscription also gives you access to any new features that are released, (after LR6 was released) like the Dehaze function.
New features are not available for LR6, but will probably be included in LR7 - if there will ever be an LR7.