1000 is the default. Your admin either neglected to migrate this custom setting over, or more likely, your admin may have increased the number of shards per index on your new cluster.
Ideally, you will want to keep within the recommended settings and rewrite logic around the limitations. That said, I think I found a post with the answer you are looking for. Changing the limit is a cluster setting that will need to be configured by an administrator:
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