Thank you for applying for a UK visa. Your visa application has been received and is under consideration. We aim to process non settlement applications within 15 working days (unless you have opted for the Priority Visa service), and settlement applications within 120 working days.
Unfortunately, the processing of your application has not been straightforward and we will be unable to decide your application within our customer service targets. We are continuing to work on your application and aim to make a decision as soon as possible.
We will write to you again if there is any change to this. Please do not attend the Visa Application Centre until you have been advised that your application has been decided and that your passport is ready for collection.
‘Settlement’ is Indefinite leave to remain (ILR) which is what you will get after you have lived in UK for a certain period of time (ie: 5 years), which is also a pathway to British Citizenship in later stage.
In your case, it most likely will be “non-settlement” which is what most applications will start off with.