SLIM (2.2.5) -- 2014/05/31
  * new features / support
    + add hash compaction
    + add hash depth
    + clearlink instruction (used with swaplink)
    + atomlist manipulation instructions
  * bug fixes
    + atomic_ruleset 
    + memory leak
    + and many minor bug fixes
  * others
    + directory structure update

SLIM (2.2.4) -- 2013/11/3
  * new features / support
    + add hlground type
    + add swaplink instructions
    
  * bug fixes
    + removeground bug with hyperlink
    + fix hlground problems
    + and minor bug fixes

SLIM (2.2.3) -- 2012/10/17
  * bug fixes
    + --delta-mem+relink problem
    + ltl stateviewer problem

SLIM (2.2.2) -- 2012/05/12
  * new features / support
    + extended state-space for optimization problems
    ++ add configure option --enable-opt-minmax
    ++ add --opt-min -opt-max option 

  * improve performances
    + modified the state compression for hyperlinks

  * bug fixes
    + transition bug for switching hash function
    + --delta-mem (function "dmem_root_make") problem
    + --d-compress --mem-enc problem
    + and minor bug fixes

  * and many codes refactored

SLIM (2.2.1)  -- 2011/12/25
  * updates for parallel LTL model checker
  ** new features / support
    + parallel execution on OSX Lion, Snow Leopard
    + uniq constraint rules for the delta-membrane method
    + new builtin foreign language interfaces for atomic operations
    + state compression using ZDelta Library (--d-compress)
    + programs using strings, floating point numbers

  ** reduce some redundant memory usages
    - atom management in membranes
    - state size

  ** improvement some time performances
    + graph isomorphism tester
    + Lv.2 profiler (calculate a Heap memory, hash conflictions, etc)
    ++ parallelization using openMP
    ++ replacement by faster hash table
    + a computational complexity of Nfreelinks procedure: O(N)-->O(1)
    + modified the mhash (a function of membranes) calculation
    ++ CHR (Uniq Constrait Rule) histories
    ++ floating point numbers using FNV-hash
    ++ membrane names

  ** bug fixes
    + graph isomorphism tester
    + builtin foreign language interfaces for atomic operations
    + memory leaks if race condition occurs in state-space
    + and minor bug fixes

  ** others
    + update the version of builtin-tcmalloc (1.6-->1.8.3)
    + fix some codes for hypergraph as MT-safe
    - remove the execution with builtin-rulesets in default
      (slim don't use builtin-rulesets/libraries in a default.
       if you want to use it, add option "--use-builtin-rule")
    - remove a option "--disable-compact"
    + and many codes refactored

SLIM (2.2.0)  -- 2011/12/24
  * new features / support
    + support Verification for hyper graph model

SLIM (2.1.7)  -- 2011/08/20
  * new features / support
    + add --show-hl option
    + improve the "REMOVEPROXIES" (membrane manager) performance
  * minor bug fixes

SLIM (2.1.3)  -- 2011/01/17
  * RunTime
    + support hyper graph representation (--hl)
  * Non-Deterministic Execution
    + update for partial order reduction (--por)

SLIM (2.1.1)  -- 2011/01/12
  * bug fix
    + fix a implementation of pthread_barrier for cygwin

SLIM (2.1.0)  -- 2011/01/11
  * LTL model checker
    + support OWCTY algorithm (--use-owcty --disable-map-h)
    + support MAP algorithm (--use-map)
    + support OWCTY + MAP heuristics (DEFAULT:--use-owcty --use-map-h)
    + support BLEDGE algorithm (--use-bledge)
  * minor bug fixes

SLIM (2.0.7)  -- 2010/10/20
  * LTL Model Checker
  ** parallelization for State Space Search on shared-memory architecture
    + support Stack-Slicing Algorithm with Dynamic Load-Balancer
    + support Verification for LTL-Safety property
    + support Reachability execution with property automata
    + add tcmalloc as multi-threaded fast memory allocator
    + implement concurrent faster hash-table

  ** improve performace
    + support Canonical Membrane representation for ltl model checking
    + improve state generate procedure using Delta-Membrane technique
    + implement Fast Graph Traversal with Process ID
    + implement new rehash technique

  ** others
    + add options    (please see --help)
    - remove options (please see --help)
    + support GraphViz (Dot Language Style) output format for State Transition Graph
    + and many bug fixes

SLIM (1.1.0)  -- 2010/06/26
  * Nondeterministic execution
    + support combination of uniq constraint & canonical membrane representation
    + support Depth Limited BFS strategy
  * Bug fixes

SLIM (1.0.0)  -- 2009/11/18
  * LTL Model Checking
    + support LTL formula
    + support never claim
  * Nondeterministic execution
    + implement canonical membrane representation
    + replace membrane isomorphism testing
    + improve membrane hashing algorithm
    + drastic memory reduction
    + change output format
  * Others
    + support external interface to C
    + support profiling for runtime
    + support new uniq constraint
    + support translation LMNtal to C
    + add LMNtal libralies
    + add -p option for profiling
    + add --mem-enc option
    + add --compact-stack option
    - remove --nd_result option
    -remove --nd_dump option
    + and many bug fixes

SLIM (0.4.0)  -- 2008/11/7
  * The conv_il was integrated to SLIM.
  * Internal compilation
   - You can give a LMNtal code to SLIM directly.
  * Model Checking Mode
  * support optimization flag
  * support system libralies
  * support -I option
  * Bug fixes

SLIM (0.3.0) -- 2008/03/04 00:55
  * module system is available

SLIM (0.2.0) -- 2008/02/21 08:55
  * new features SHOULD be described here

SLIM (0.1.0) -- 2007/10/13 17:30
  * new features SHOULD be described here
