mamp change php version

1As mentioned by @Scott in the comments under your question:
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3Your here is the right link. Use the bottom answer to rename the bin/php directory. The MAMP preference pane will show the 2 latest versions in the php directory. – Scott Eisenberg
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5And the answer in that links is:
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7First stop the Server if its running. Go to "/Applications/MAMP/bin/", rename the PHP Version you don't need (MAMP is only allowed to use 2 PHP Versions), e.g. "_php5.2.17". Now MAMP will use the php versions that are left. Go to the MAMP Manager and then settings, then switch to the php version you need.
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9In my case (and similarly yours), I renamed the folder named php7.1.1 to _php7.1.1 and now MAMP shows me 5.6.30 and 7.0.15 in the preferences pane.