From 08720b46129c46c83553aa6d353b3dd40bb4bee5 Mon Sep 17 00:00:00 2001
From: Andy Wilkinson <awilkinson@pivotal.io>
Date: Tue, 15 Dec 2015 14:28:44 +0000
Subject: [PATCH] Document need to avoid Logback placeholder format in logging
 properties

Closes gh-4731
---
 .../src/main/asciidoc/spring-boot-features.adoc           | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc b/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc
index d3c86f0bfd4..4fcd6233ba5 100644
--- a/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc
+++ b/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc
@@ -1231,6 +1231,14 @@ To help with the customization some other properties are transferred from the Sp
 All the logging systems supported can consult System properties when parsing their
 configuration files.  See the default configurations in `spring-boot.jar` for examples.
 
+[TIP]
+====
+If you want to use a placeholder in a logging property, you should use
+<<boot-features-external-config-placeholders-in-properties,Spring Boot's syntax>> and not
+the syntax of the underlying framework. Notably, if you're using Logback, you should use
+`:` as the delimiter between a property name and its default value and not `:-`.
+====
+
 [TIP]
 ====