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# Release 2.16 (2023-05-31)

- Speed-up of downloads from binary caches. The number of parallel downloads (also known as substitutions) has been separated from the `--max-jobs` setting. The new setting is called `max-substitution-jobs`. The number of parallel downloads is now set to 16 by default (previously, the default was 1 due to the coupling to build jobs).

- The function `builtins.replaceStrings` is now lazy in the value of its second argument `to`. That is, `to` is only evaluated when its corresponding pattern in `from` is matched in the string `s`.