Is PhD funding updatable?
I cannot speak for the UK/EU but in the US, your funding is not generally "updateable". It always increases by a non significant inflationary rate amount every year.

The only way in which funding is generally updated is if you acquire for yourself some other funding sources which replace your base funding because they have a higher stipend level eg. NSF graduate fellowship, MSR fellowship, Facebook fellowship etc.

The other way in which my funding has been supplemented at least in my case is my ex-adviser used to give me some more funds as research expenses out of his discretionary funding (or other grant funding, I am not sure) because I was involved in extra projects (not directly related to my own but I was brought in as an analyst) on his request.

I do not think that publishing in great journals/conferences will bring in more funding for you (in general)