Possible enhancements and directions of development, in no particular
order:

- Rewrite FileAppender to use OS specific file handling to allow
  RollingFileAppender to roll log files shared between multiple
  processes even on Windows.

- Improve error handling
  - allow not to throw exceptions
  - create hooks to allow users to override behaviour

- EventLog library appender.

- org.apache.log4j.net.ZeroConfSocketHubAppender.

- Reading log4j-like XML configuration files.

- More flexible events format for transport over network. ASN.1? XML?
  YAML? JSON?.

- Modular PatternLayout; public PatternConverter classes; user defined
  format specifiers.

- More flexible log file rotation, like keeping only last 31 days of
  logs produced by DailyRollingFileAppender, rotate at midnight, etc.

- Installers for Debian, Ubuntu, Windows/Qt Creator.

- Allow specifying codecvt facet for FileAppender through properties.

- Custom codecvt facet for use FileAppender using log4cplus' internal
  wchar_t <-> chart conversion routines.

- Research possible use of Valgrind at compile time.

- Research possible use of -fmudflap.

- Improve CMake configuration checks (TLS) to be on par with
  Autoconf's.

- ConsoleAppender or specialized appender with colored output per log
  level for *NIX platforms. Win32ConsoleAppender already has some
  support for this.

- Graylog2/GELF appender. See
  <https://github.com/Graylog2/graylog2-docs/wiki/GELF>.