The most common and most likely answer to this crossword clue is the 8 letter word REHASHES
I've seen this crossword clue in Financial Times
R
E
H
A
S
H
E
S
Buddy explains!
The straight part
We know that "new arrangements for old things" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case new arrangements for old things = rehashes.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.
What does REHASHES mean?
REHASHES noun- Something reworked, or made up from old materials.
- A recomputation of the structure of a hash table, taking into account any newly added items.
- To repeat with minor variation.
- To analyze a prior contentious or embarrassing event.
- To recompute the structure of a hash table, taking into account any newly added items.