# Document history for transit gateways
<a name="doc-history"></a>

The following table describes the releases for transit gateways.

| Change | Description | Date | 
| --- |--- |--- |
| [Client VPN attachments](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-client-vpn-attachments.html) | Create a Client VPN attachment to connect a transit gateway to a Client VPN endpoint. | April 20, 2026 | 
| [Flexible Cost Allocation](https://docs.aws.amazon.com/vpc/latest/tgw/metering-policy.html) | Configure flexible cost allocation policies to control how data processing and transfer costs are allocated across your organization. | November 20, 2025 | 
| [Encryption Support for transit gateways](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-encryption-support.html) | Managing Encryption Support on transit gateways to enforce encryption-in-transit for all traffic. | November 20, 2025 | 
| [Network function attachments](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-nf-fw.html) | Create a network function attachment to connect a transit gateway directly to AWS Network Firewall. | June 16, 2025 | 
| [Security group referencing support](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-vpc-attachments.html#vpc-attachment-security) | You can now reference a security group across VPCs attached to a transit gateway. | September 25, 2024 | 
| [AWS Transit Gateway Quotas](https://docs.aws.amazon.com/vpc/latest/tgw/transit-gateway-quotas.html#bandwidth-quotas) | Bandwidth limits were added. | August 14, 2023 | 
| [AWS Transit Gateway Flow Logs](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-flow-logs.html) | Transit Gateways now support Transit Gateway Flow Logs, allowing you to monitor and log network traffic between transit gateways. | July 14, 2022 | 
| [Transit gateway policy tables](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-policy-tables.html) | Use policy tables to set up dynamic routing for transit gateways for automatically exchanging routing and reachability information with peered transit gateway types. | July 13, 2022 | 
| [Network Manager User Guide](#doc-history) | Network Manager was created as a standalone guide, and is no longer included as part of the *AWS Transit Gateway User Guide*. | December 2, 2021 | 
| [Peering attachments](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-peering.html) | You can create a peering connection with a transit gateway in the same Region. | December 1, 2021 | 
| [Transit Gateway Connect](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-connect.html) | You can establish a connection between a transit gateway and third-party virtual appliances running in a VPC. | December 10, 2020 | 
| [Appliance mode](#doc-history) | You can enable appliance mode on a VPC attachment to ensure that bidirectional traffic flows through the same Availability Zone for the attachment. | October 29, 2020 | 
| [Prefix list references](#doc-history) | You can reference a prefix list in your transit gateway route table. | August 24, 2020 | 
| [Modify transit gateway](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-transit-gateways.html#tgw-modifying) | You can modify the configuration options for your transit gateway. | August 24, 2020 | 
| [CloudWatch metrics for transit gateway attachments](https://docs.aws.amazon.com/vpc/latest/tgw/transit-gateway-cloudwatch-metrics.html#transit-gateway-attachment-metrics) | You can view CloudWatch metrics for individual transit gateway attachments. | July 6, 2020 | 
| [Network Manager Route Analyzer](https://docs.aws.amazon.com/network-manager/latest/tgwnm/route-analyzer.html) | You can analyze the routes in your transit gateway route tables in your global network. | May 4, 2020 | 
| [Peering attachments](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-peering.html) | You can create a peering connection with a transit gateway in another Region. | December 3, 2019 | 
| [Multicast support](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-multicast-overview.html) | Transit Gateway supports routing multicast traffic between subnets of attached VPCs and serves as a multicast router for instances sending traffic destined for multiple receiving instances. | December 3, 2019 | 
| [AWS Network Manager](https://docs.aws.amazon.com/network-manager/latest/tgwnm/) | You can visualize and monitor your global networks that are built around transit gateways. | December 3, 2019 | 
| [AWS Direct Connect support](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-dcg-attachments.html) | You can use an Direct Connect gateway to connect your Direct Connect connection over a transit virtual interface to the VPCs or VPNs attached to your transit gateway. | March 27, 2019 | 
| [Initial release](#doc-history) | This release introduces transit gateways. | November 26, 2018 |