This is a bit interesting that I found through undermentioned sources. For instance, it is an overhaul project for JF-17 started in China. The article also states that subjected project/overhaul line will be doing the job from 2nd Gen to 3rd Generation and we all understand that Chinese 2nd Generation term is equal to other 3rd generation for the rest of the world hence, Chinese 3rd Generation indicates as 4th Generation overhauling. My understanding could be wrong too but I found it to post so that we can discuss and understand much better. The machine repair would be most probably to indicate about structure stengthening/Airframe repair on par with 4th Generation plans. So by the same understanding, one can assume that JF-17 overhaul will actually move its standard from mere 4th Generation to ++ standard. For an example we see how Fighting Falcon (F-16) proceeded with upgrades and structure strengthening. It may be mentioned as the overhaul will actually take the air-frame strength to coup with future weapon advancement, payload etc.
My understanding could be wrong or incorrect in interpretation hence, you all are welcome to discuss.
Chinese friends are hereby called upon to share a better translated version and Google Translate does not help fully in this regard.
I will quote a paragraph from the same article, for the time being.
The first "Fierce Dragon" aircraft overhaul line project started
This is a very vague and short article. Basically, it didn't mention much. I can bet due to the sensitivity of the issue. From what I understand. It shall be block 1 upgrade to block 2 by AVIC for the initial batch of JF-17 which I believe its the JF-17 block 1. It talks about upgrade of generation from two to three. But how do you define the generation? Is it Chinese classification of aviation generation or purely in terms of understanding solely based on JF-17?