Unescaped left brace in regex is deprecated, passed through in regex

[paternal]

When using the report and getfield plugins, I get the following warnings:

Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/{{ <-- HERE \$page}}/ at ikiplugins/IkiWiki/Plugin/report.pm line 98.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(\\?){{ <-- HERE \$([-\w]+)}}/ at ikiplugins/IkiWiki/Plugin/getfield.pm line 73.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(\\?){{ <-- HERE \$([-\w/]+)#([-\w]+)}}/ at ikiplugins/IkiWiki/Plugin/getfield.pm line 76.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(\\?){{ <-- HERE \+\$([-\w]+)\+}}/ at ikiplugins/IkiWiki/Plugin/getfield.pm line 84.
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/(\\?){{ <-- HERE \+\$([-\w/]+)#([-\w]+)\+}}/ at ikiplugins/IkiWiki/Plugin/getfield.pm line 86.

Using:

• ikiwiki version 3.20160121
• up-to-date ikiplugins : 4d2da05
• perl 5, version 22, subversion 1 (v5.22.1) built for x86_64-linux-gnu-thread-multi
• on Debian Stretch.

Thanks for your work!