Getting error when DebugScreen needs to show debug screen

[i07]

Any help would be appreciated.

The details:

Using Maven 4

versions of spark dependencies in project.

<dependency>
  <groupId>com.sparkjava</groupId>
  <artifactId>spark-core</artifactId>
  <version>2.5.5</version>
</dependency>
<dependency>
  <groupId>com.sparkjava</groupId>
  <artifactId>spark-debug-tools</artifactId>
  <version>0.5</version>
</dependency>
<dependency>
  <groupId>com.sparkjava</groupId>
  <artifactId>spark-template-freemarker</artifactId>
  <version>2.3</version>
</dependency>

Partial dump of error message:

On my end, forced an exception

Caught Exception:

FreeMarker template error:
The following has evaluated to null or missing:
==> message [in template "freemarker/base.ftl" at line 6, column 14]

Tip: If the failing expression is known to be legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)??

FTL stack trace ("~" means nesting-related):
- Failed at: ${message.get("WEBSITE_TITLE")} [in template "freemarker/base.ftl" in macro "masterTemplate" at line 6, column 12]
- Reached through: @layout.masterTemplate title="index" [in template "freemarker/index/index.ftl" at line 2, column 1]

This is the DebugScreen bit:

Caught Exception Rendering DebugScreen:

java.lang.IllegalArgumentException: freemarker.core._MiscTemplateException: Can't convert boolean to string automatically, because the "boolean_format" setting was "true,false", which is the legacy default computer-language format, and hence isn't accepted.

Tip: If you just want "true"/"false" result as you are generting computer-language output, use "?c", like ${myBool?c}.

Tip: You can write myBool?string('yes', 'no') and like to specify boolean formatting in place.

Tip: If you need the same two values on most places, the programmers should set the "boolean_format" setting to something like "yes,no".

FTL stack trace ("~" means nesting-related):
- Failed at: ${data[k]} auto-escaped [in template "debugscreen.ftl" at line 107, column 54]