I was upgrading our strapi dependencies from 3.6.8 to 3.6.10 before making the leap to v4.
We have 15 strapi related dependencies altogether in our project:
"strapi": "3.6.8",
"strapi-admin": "3.6.8",
"strapi-connector-bookshelf": "3.6.8",
"strapi-hook-algolia": "^3.8.0",
"strapi-plugin-content-manager": "3.6.8",
"strapi-plugin-content-type-builder": "3.6.8",
"strapi-plugin-email": "3.6.8",
"strapi-plugin-i18n": "3.6.8",
"strapi-plugin-oembed": "^0.4.0",
"strapi-plugin-sentry": "^3.6.5",
"strapi-plugin-upload": "3.6.8",
"strapi-plugin-users-permissions": "3.6.8",
"strapi-provider-email-mcmandrill": "file:providers/strapi-provider-email-mcmandrill",
"strapi-provider-upload-canto": "file:providers/strapi-provider-upload-canto",
"strapi-utils": "3.6.8"
I upgraded every dependency one by one and started strapi after each dependency. The moment I upgraded strapi-utils from 3.6.8 to 3.6.10, I got warnings similar to the ones by the OP:
MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 drain listeners added to [WriteStream]. Use emitter.setMaxListeners() to increase limit
First I deleted the .cache, build and node_modules folder and re-installed the dependencies.
Then, after starting strapi again, I received the warning again.
Only after I deleted the package-lock.json as well (which I originally wanted to avoid because now I get unfixed versions for my first- and third-party dependencies) and re-installed the dependencies, then upon starting strapi again, the warning was gone.
Now I’m sitting here, trying to figure out if I can live with that fix or if I should invest some time and energy to find out which of the countless transitive dependencies fixed in the package-lock.json is causing problems in my environment 