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docs/readme.en.md

@@ -284,6 +284,7 @@ Fakes are separate generated by nfqws packets carrying false information for DPI
   This mode may break NAT and may not work with iptables if masquerade is used, even from the router itself.
   Works with nftables properly. Likely requires external IP address (some ISPs pass these packets through their NAT).
 * **autottl** tries to automatically guess hop count to the server and compute TTL by adding some delta value that can be positive or negative.
+  Positive deltas must be preceeded by unary `+` sign. Deltas without any unary sign are treated negative for old versions compatibility reasons.
   This tech relies on well known TTL default values used by OS : 64,128,255.
   nfqws needs first incoming packet to see it's TTL. You must redirect it too.
   If resulting value TTL is outside the range (min,max) then its normalized to min or max.