Starting with v3.0.0, framework will unconditionally run service local installation of serverless if its found.
Starting with v2.0.0, instead of globally installed version, CLI will by default run service local installation of serverless if it's found.
You may adapt to this behavior now by setting enableLocalInstallationFallback: true in your service config. Alternatively you may opt-out by setting it to false (still that'll be ineffective starting from v3.0.0 where support for this setting will be dropped, and CLI will unconditionally favor locally installed serverless installations)
provider.httpApi.timeout and functions[].events[].httpApi.timeout settings will no longer be recognized with v2.0.0.
Endpoints are configured to automatically follow timeout setting as configured on functions (with extra margin needed to process HTTP request on AWS side)
Support for slss command will be removed with v2.0.0. Use sls or serverless instead.
maximumEventAge and maximumRetryAttempts should be defined directly at function level. Support for those settings on destinations level, will be removed with v2.0.0
Default HTTP API Payload version will be switched to 2.0 with next major release (For more details see payload format documentation)
Configure httpApi.payload explicitly to ensure seamless migration.
It appears you rely on no longer maintained Node.js version.
Please upgrade to use at least Node.js v10 (It's recommended to use LTS version, as listed at https://nodejs.org/en/)
Please use onUnauthenticatedRequest instead. allowUnauthenticated will be removed with v2.0.0
Please use bin/serverless.js instead. bin/serverless will be removed with v2.0.0