Command line:

• Added --relative-path

Improved checks to detect more bugs:

• improved checking for buffer overruns on dynamically allocated memory (#3569)
• when variable is compared against a value in condition, the variable value is known in the conditional block.
• null pointer checking - handle more standard functions and improved checking of loops
  • more standard functions are checked (#1171, #410)
  • improved checking of loops (#1927)
  • dangerous conditions (#3518)
• detect more bugs related to std::find and string::find usage (#3162)
• detect more sign extension problems (#3637)
• detect redundant .c_str() for strings (#1079)
• invalid pointer cast from float* to double* (#1255)
• more strict about int vs. bool (#1877)
• Preprocessor: extract more configurations => more code is checked
• Unused functions - fixed false negatives for functions that returns reference
• Better checking of sizeof
• Improved "unused private function" checking

GUI:

• Faster recheck: The "Recheck files" only rechecks the files that has been modified since the last scan

For more details, see this page:

http://sourceforge.net/apps/trac/cppcheck/milestone/1.54