--- title: "Project Calico 2.1 Released!" source: "https://www.tigera.io/blog/project-calico-2-1-released/" --- [Technical Blog](https://www.tigera.io/category/technical-blog/) # Project Calico 2.1 Released! By [Tom Denham](https://www.tigera.io/blog/author/tomdenham/) on Mar 21, 2017 • 2 min read ## **#ReleaseTheCalico** We’re proud to announce the release of [Project Calico 2.1](http://docs.projectcalico.org/v2.1/releases/).  This version brings with it numerous features to make dynamically scaling and securing your network even easier. From enhancements to the Docker plugin to improved IP and Host Protection policies, 2.1 promises even more versatility, as well as significant performance benefits. Here are just some of our favorite 2.1 enhancements: **• Improved IP Auto-Detection Options** To make networking even easier, the [calicoctl](http://docs.projectcalico.org/v2.1/reference/calicoctl/commands/node/run#ip-autodetection-method-examples) command line took, and the [calico/node](http://docs.projectcalico.org/v2.1/reference/node/configuration#ip-autodetection-methods) agent now ship with improved IP auto-detection options.**• New Cross-Subnet Option in IP-in-IP Mode for Traffic Handling** Calico now supports a new option for the [IP-in-IP mode](http://docs.projectcalico.org/v2.1/usage/configuration/ip-in-ip#configuring-cross-subnet-ip-in-ip) where traffic is only encapsulated when it’s destined to subnets with intermediate infrastructure lacking Calico route awareness – for example, across heterogeneous public clouds or on AWS where traffic is crossing availability zones/ regions. **• Host Protection Now Applies to Forwarded Traffic** Calico [Host Protection](http://docs.projectcalico.org/master/getting-started/bare-metal/bare-metal) now applies to [forwarded traffic](http://docs.projectcalico.org/master/getting-started/bare-metal/bare-metal), letting you use Calico to dynamically secure a NAT gateway or router. **• Untracked Policies and Support for High Load Applications** Calico [Host Protection](http://docs.projectcalico.org/v2.1/getting-started/bare-metal/bare-metal#untracked-policy)now supports an [“untracked” policy](http://docs.projectcalico.org/v2.1/getting-started/bare-metal/bare-metal) to bypass connection tracking, which is useful for applications that have very frequent but short-lived connections (e.g. memcachedb). **• Endpoint Labeling Support for Docker** Libnetwork plugin for Docker now supports [endpoint labeling](http://docs.projectcalico.org/v2.1/getting-started/docker/tutorials/security-using-docker-labels-and-calico-policy), making it possible to use advanced network policies with Docker. **• Improved IP Selection Configurations** Several improvements for IP selection and management have been made to the [Calico CNI](http://docs.projectcalico.org/v2.1/reference/cni-plugin/configuration) plugin.  It is now possible to choose specific IP addresses, or to allocate addresses from specific IP Pools using config or Kubernetes annotations. **• Felix 100% Written in Go** With the last pieces of Python code rewritten, Felix and the calico/node containers are completely written in [Go](http://golang.org/), offering significant performance and occupancy [benefits](http://www.quora.com/What-advantages-does-the-Go-programming-language-have-over-Python-or-vice-versa). Of course, you can see the full list as well as specific updates to individual components in the [2.1 Release Notes](http://docs.projectcalico.org/v2.1/releases/). What do you think about these new features? Tweet [@ProjectCalico](http://twitter.com/projectcalico) with hashtag [#ReleaseTheCalico](http://twitter.com/hashtag/releasethecalico) Have Questions about this Release? Ask them on [Slack](https://www.tigera.io/project-calico/community/) [Open Source](https://www.tigera.io/tags/open-source/)[Release](https://www.tigera.io/tags/release/)[Project Calico](https://www.tigera.io/tags/project-calico/) ## Related posts [![What’s new in Calico: Spring 2026 Release](https://www.tigera.io/app/uploads/2026/06/Whats-New-in-Calico-NEW-TEMPLATE-2026.png)](https://www.tigera.io/blog/whats-new-in-calico-spring-2026-release/) [Company Blog](https://www.tigera.io/category/company-blog/) #### [What’s new in Calico: Spring 2026 Release](https://www.tigera.io/blog/whats-new-in-calico-spring-2026-release/) By [Veronika Smolik](https://www.tigera.io/blog/author/veronika-smolik/) on Jun 2, 2026 Kubernetes has come a long way since its debut in 2014. It’s gone from running a couple of containerized microservices to orchestrating fleets of production workloads spanning everything from AI agents to full scale VMs... 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