The most common and most likely answer to this crossword clue is the 4 plus 2 plus 2 plus 4 letter word BANG UP TO DATE
I've seen this crossword clue in The Guardian
B
A
N
G
U
P
T
O
D
A
T
E
More clues leading to the result BANG UP TO DATE
Buddy explains!

The straight part
We know that "Very modern" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case very modern = bang up to date.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.