Help to update sage

Hi everyone,
i develop a theme with sage 8.1.1 (less) afterwards another theme with sge 8.4.2 (sass)

Today i wanted to modify 8.1.1 css but when i launch

gulp --production

i have those errors

Warning: gulp version mismatch:
[16:51:43] Global gulp is 3.9.1
[16:51:43] Local gulp is 3.8.11
’styles’ errored after 14 s
[16:52:13] Error: libsass bindings not found. Try reinstalling node-sass?
‘build’ errored after 18 s
[16:52:13] Error: [object Object]
at formatError (/usr/lib/node_modules/gulp/bin/gulp.js:169:10)
at Gulp. (/usr/lib/node_modules/gulp/bin/gulp.js:195:15)
at emitOne (events.js:82:20)
at Gulp.emit (events.js:169:7)
at Gulp.Orchestrator._emitTaskDone

I have to update sage 8.1.1 to latest version?
How?

many thanks

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