anchor.diff:      ok.
   
   
  +get_option(Key, Opts) ->
  +    snmp_misc:get_option(Key, Opts).
  +
   get_option(Key, Opts, Default) ->
       snmp_misc:get_option(Key, Opts, Default).
   
  
positive.code: 
  %% Downgrade
  %%
  code_change({down, _Vsn}, S1, downgrade_to_pre_4_17_3) ->
      #state{type               = Type, 
  	   parent             = Parent, 
  	   worker             = Worker, 
  	   worker_state       = WorkerState,
  	   set_worker         = SetWorker, 
  	   multi_threaded     = MT, 
  	   ref                = Ref, 
  	   vsns               = Vsns,
  	   nfilters           = NF,
  	   note_store         = NoteStore,
  	   mib_server         = MS, 
  	   net_if             = NetIf, 
  	   net_if_mod         = NetIfMod, 
  	   backup             = Backup,
  	   disco              = Disco,
  	   mibs_cache_request = MCR} = S1, 
      S2 = {state, 
  	  type               = Type, 
  	  parent             = Parent, 
  	  worker             = Worker, 
  	  worker_state       = WorkerState,
  	  set_worker         = SetWorker, 
  	  multi_threaded     = MT, 
  	  ref                = Ref, 
  	  vsns               = Vsns,
  	  nfilters           = NF,
  	  note_store         = NoteStore,
  	  mib_server         = MS, 
  	  net_if             = NetIf, 
  	  net_if_mod         = NetIfMod, 
  	  backup             = Backup,
  	  disco              = Disco,
  	  mibs_cache_request = MCR}, 
      {ok, S2};
  
  %% Upgrade
  %%
  code_change(_Vsn, S1, upgrade_from_pre_4_17_3) ->
      {state, 
       type               = Type, 
       parent             = Parent, 
       worker             = Worker, 
       worker_state       = WorkerState,
       set_worker         = SetWorker, 
       multi_threaded     = MT, 
       ref                = Ref, 
       vsns               = Vsns,
       nfilters           = NF,
       note_store         = NoteStore,
       mib_server         = MS, 
       net_if             = NetIf, 
       net_if_mod         = NetIfMod, 
       backup             = Backup,
       disco              = Disco,
       mibs_cache_request = MCR} = S1,
      S2 = #state{type               = Type, 
  		parent             = Parent, 
  		worker             = Worker, 
  		worker_state       = WorkerState,
  		set_worker         = SetWorker, 
  		multi_threaded     = MT, 
  		ref                = Ref, 
  		vsns               = Vsns,
  		nfilters           = NF,
  		note_store         = NoteStore,
  		mib_server         = MS, 
  		net_if             = NetIf, 
  		net_if_mod         = NetIfMod, 
  		backup             = Backup,
  		disco              = Disco,
  		mibs_cache_request = MCR,
  		gb_max_vbs         = ?DEFAULT_GB_MAX_VBS}, 
      {ok, S2};
  
  code_change(_Vsn, S, _Extra) ->
      {ok, S}.
  
negative.code:     get_option(mibs, Opts, []).
  
  get_mib_storage(Opts) ->
      get_option(mib_storage, Opts).
  
  get_set_mechanism(Opts) ->
      get_option(set_mechanism, Opts, snmpa_set).
  