You should probably use JSON::true , instead of 'true'. 
>perl -MJSON -E  "say to_json({x=>33, params=>{'history'=>JSON::true},
+})"
{"params":{"history":true},"x":33}

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        The best defense against logic is ignorance.

In reply to Re: encoding a boolean in JSON::RPC::Client by NetWallah
in thread encoding a boolean in JSON::RPC::Client by bigswifty00000

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