Apache Camel 4.x Upgrade Guide

This document is for helping you upgrade your Apache Camel application from Camel 4.x to 4.y. For example, if you are upgrading Camel 4.0 to 4.2, then you should follow the guides from both 4.0 to 4.1 and 4.1 to 4.2.

The Camel Upgrade Recipes project provides automated assistance for some common migration tasks. Note that manual migration is still required. See the documentation page for details.

Upgrading Camel 4.22 to 4.23

camel-a2a - webhook URL address classification

Push notification webhook URLs are now classified by the address the host resolves to, using the same rules whether the host is written as an IP literal or as a name. Previously a few ranges were recognised only in literal form, and host names were partly classified by how they were spelled.

Webhook URLs are now rejected when the host resolves into any of the following, in addition to the loopback, wildcard, link-local and site-local ranges that were already rejected:

IPv6 unique local addresses, fc00::/7
IPv4-compatible IPv6 addresses, ::a.b.c.d, when the embedded IPv4 address is itself non-global
NAT64 addresses under the well-known prefix 64:ff9b::/96, when the embedded IPv4 address is itself non-global
6to4 addresses under 2002::/16, when the embedded IPv4 address is itself non-global
The shared address space used for carrier-grade NAT, 100.64.0.0/10

NAT64 and 6to4 addresses carrying a globally routable IPv4 address remain allowed, so an IPv6-only deployment can still reach public webhook endpoints through a translation prefix.

In the other direction, host names are no longer rejected on the basis of their spelling. Names beginning with fc or fd, such as fcm.googleapis.com, were previously refused because those are the leading hex digits of the IPv6 unique local prefixes; they are now resolved and classified like any other name.

Set allowLocalWebhookUrls=true to permit loopback targets during local development. That option is unchanged and still does not permit any of the ranges above.