6 files changed, 135 insertions, 74 deletions

diff --git a/indra/newview/llenvironment.cpp b/indra/newview/llenvironment.cpp
index 3a030bb09d..20021fb075 100644
--- a/indra/newview/llenvironment.cpp
+++ b/indra/newview/llenvironment.cpp
@@ -76,6 +76,7 @@ namespace
     const std::string KEY_DAYNAME("day_name");
     const std::string KEY_DAYNAMES("day_names");
     const std::string KEY_DAYOFFSET("day_offset");
+    const std::string KEY_ENVVERSION("env_version");
     const std::string KEY_ISDEFAULT("is_default");
     const std::string KEY_PARCELID("parcel_id");
     const std::string KEY_REGIONID("region_id");
@@ -329,6 +330,8 @@ const LLUUID LLEnvironment::KNOWN_SKY_SUNSET("95882e1b-7741-f082-d9d6-3a34ec644c
 const LLUUID LLEnvironment::KNOWN_SKY_MIDNIGHT("d8e50d02-a15b-17a7-3425-523bc20f67b8");
 
 const S32 LLEnvironment::NO_TRACK(-1);
+const S32 LLEnvironment::NO_VERSION(-3); // For viewer sided change, like ENV_LOCAL. -3 since -1 and -2 are taken by parcel initial server/viewer version
+const S32 LLEnvironment::VERSION_CLEANUP(-4); // for cleanups
 
 const F32 LLEnvironment::SUN_DELTA_YAW(F_PI);   // 180deg 
 
@@ -360,6 +363,7 @@ void LLEnvironment::initSingleton()
     gAgent.addParcelChangedCallback([this]() { onParcelChange(); });
 
     //TODO: This frequently results in one more request than we need.  It isn't breaking, but should be nicer.
+    // We need to know new env version to fix this, without it we can only do full re-request
     LLRegionInfoModel::instance().setUpdateCallback([this]() { requestRegion(); });
     gAgent.addRegionChangedCallback([this]() { onRegionChange(); });
 
@@ -551,7 +555,7 @@ LLEnvironment::DayInstance::ptr_t LLEnvironment::getEnvironmentInstance(LLEnviro
 }
 
 
-void LLEnvironment::setEnvironment(LLEnvironment::EnvSelection_t env, const LLSettingsDay::ptr_t &pday, LLSettingsDay::Seconds daylength, LLSettingsDay::Seconds dayoffset)
+void LLEnvironment::setEnvironment(LLEnvironment::EnvSelection_t env, const LLSettingsDay::ptr_t &pday, LLSettingsDay::Seconds daylength, LLSettingsDay::Seconds dayoffset, S32 env_version)
 {
     if ((env < ENV_EDIT) || (env >= ENV_DEFAULT))
     {   
@@ -567,11 +571,11 @@ void LLEnvironment::setEnvironment(LLEnvironment::EnvSelection_t env, const LLSe
     environment->animate();
 
     if (!mSignalEnvChanged.empty())
-        mSignalEnvChanged(env);
+        mSignalEnvChanged(env, env_version);
 }
 
 
-void LLEnvironment::setEnvironment(LLEnvironment::EnvSelection_t env, LLEnvironment::fixedEnvironment_t fixed)
+void LLEnvironment::setEnvironment(LLEnvironment::EnvSelection_t env, LLEnvironment::fixedEnvironment_t fixed, S32 env_version)
 {
     if ((env < ENV_EDIT) || (env >= ENV_DEFAULT))
     {
@@ -595,12 +599,12 @@ void LLEnvironment::setEnvironment(LLEnvironment::EnvSelection_t env, LLEnvironm
 
 
     if (!mSignalEnvChanged.empty())
-        mSignalEnvChanged(env);
+        mSignalEnvChanged(env, env_version);
 
     /*TODO: readjust environment*/
 }
 
-void LLEnvironment::setEnvironment(LLEnvironment::EnvSelection_t env, const LLSettingsBase::ptr_t &settings)
+void LLEnvironment::setEnvironment(LLEnvironment::EnvSelection_t env, const LLSettingsBase::ptr_t &settings, S32 env_version)
 {
     DayInstance::ptr_t environment = getEnvironmentInstance(env);
 
@@ -647,22 +651,33 @@ void LLEnvironment::setEnvironment(LLEnvironment::EnvSelection_t env, const LLSe
     }
 }
 
-void LLEnvironment::setEnvironment(EnvSelection_t env, const LLUUID &assetId)
+void LLEnvironment::setEnvironment(EnvSelection_t env, const LLUUID &assetId, S32 env_version)
 {
     setEnvironment(env, assetId, LLSettingsDay::DEFAULT_DAYLENGTH, LLSettingsDay::DEFAULT_DAYOFFSET);
 }
 
 
-void LLEnvironment::setEnvironment(EnvSelection_t env, const LLUUID &assetId, LLSettingsDay::Seconds daylength, LLSettingsDay::Seconds dayoffset)
+void LLEnvironment::setEnvironment(EnvSelection_t env,
+                                   const LLUUID &assetId,
+                                   LLSettingsDay::Seconds daylength,
+                                   LLSettingsDay::Seconds dayoffset,
+                                   S32 env_version)
 {
     LLSettingsVOBase::getSettingsAsset(assetId,
-        [this, env, daylength, dayoffset](LLUUID asset_id, LLSettingsBase::ptr_t settings, S32 status, LLExtStat) 
+        [this, env, daylength, dayoffset, env_version](LLUUID asset_id, LLSettingsBase::ptr_t settings, S32 status, LLExtStat)
         {
-            onSetEnvAssetLoaded(env, asset_id, settings, daylength, dayoffset, TRANSITION_DEFAULT, status); 
+            onSetEnvAssetLoaded(env, asset_id, settings, daylength, dayoffset, TRANSITION_DEFAULT, status, env_version);
         });
 }
 
-void LLEnvironment::onSetEnvAssetLoaded(EnvSelection_t env, LLUUID asset_id, LLSettingsBase::ptr_t settings, LLSettingsDay::Seconds daylength, LLSettingsDay::Seconds dayoffset, LLSettingsBase::Seconds transition, S32 status)
+void LLEnvironment::onSetEnvAssetLoaded(EnvSelection_t env,
+                                        LLUUID asset_id,
+                                        LLSettingsBase::ptr_t settings,
+                                        LLSettingsDay::Seconds daylength,
+                                        LLSettingsDay::Seconds dayoffset,
+                                        LLSettingsBase::Seconds transition,
+                                        S32 status,
+                                        S32 env_version)
 {
     if (!settings || status)
     {
@@ -687,7 +702,7 @@ void LLEnvironment::clearEnvironment(LLEnvironment::EnvSelection_t env)
     mEnvironments[env].reset();
 
     if (!mSignalEnvChanged.empty())
-        mSignalEnvChanged(env);
+        mSignalEnvChanged(env, VERSION_CLEANUP);
 
     /*TODO: readjust environment*/
 }
@@ -1055,7 +1070,7 @@ void LLEnvironment::recordEnvironment(S32 parcel_id, LLEnvironment::EnvironmentI
         if (!envinfo->mDayCycle)
         {
             clearEnvironment(ENV_PARCEL);
-            setEnvironment(ENV_REGION, LLSettingsDay::GetDefaultAssetId(), LLSettingsDay::DEFAULT_DAYLENGTH, LLSettingsDay::DEFAULT_DAYOFFSET);
+            setEnvironment(ENV_REGION, LLSettingsDay::GetDefaultAssetId(), LLSettingsDay::DEFAULT_DAYLENGTH, LLSettingsDay::DEFAULT_DAYOFFSET, envinfo->mEnvVersion);
             updateEnvironment();
         }
         else if (envinfo->mDayCycle->isTrackEmpty(LLSettingsDay::TRACK_WATER)
@@ -1063,13 +1078,13 @@ void LLEnvironment::recordEnvironment(S32 parcel_id, LLEnvironment::EnvironmentI
         {
             LL_WARNS("LAPRAS") << "Invalid day cycle for region" << LL_ENDL;
             clearEnvironment(ENV_PARCEL);
-            setEnvironment(ENV_REGION, LLSettingsDay::GetDefaultAssetId(), LLSettingsDay::DEFAULT_DAYLENGTH, LLSettingsDay::DEFAULT_DAYOFFSET);
+            setEnvironment(ENV_REGION, LLSettingsDay::GetDefaultAssetId(), LLSettingsDay::DEFAULT_DAYLENGTH, LLSettingsDay::DEFAULT_DAYOFFSET, envinfo->mEnvVersion);
             updateEnvironment();
         }
         else
         {
             LL_INFOS("LAPRAS") << "Setting Region environment" << LL_ENDL;
-            setEnvironment(ENV_REGION, envinfo->mDayCycle, envinfo->mDayLength, envinfo->mDayOffset);
+            setEnvironment(ENV_REGION, envinfo->mDayCycle, envinfo->mDayLength, envinfo->mDayOffset, envinfo->mEnvVersion);
             mTrackAltitudes = envinfo->mAltitudes;
         }
 
@@ -1098,7 +1113,7 @@ void LLEnvironment::recordEnvironment(S32 parcel_id, LLEnvironment::EnvironmentI
         }
         else
         {
-            setEnvironment(ENV_PARCEL, envinfo->mDayCycle, envinfo->mDayLength, envinfo->mDayOffset);
+            setEnvironment(ENV_PARCEL, envinfo->mDayCycle, envinfo->mDayLength, envinfo->mDayOffset, envinfo->mEnvVersion);
         }
     }
 
@@ -1470,7 +1485,8 @@ LLEnvironment::EnvironmentInfo::EnvironmentInfo():
     mIsDefault(false),
     mIsLegacy(false),
     mDayCycleName(),
-    mNameList()
+    mNameList(),
+    mEnvVersion(INVALID_PARCEL_ENVIRONMENT_VERSION)
 {
 }
 
@@ -1526,6 +1542,17 @@ LLEnvironment::EnvironmentInfo::ptr_t LLEnvironment::EnvironmentInfo::extract(LL
         }
     }
 
+    if (environment.has(KEY_ENVVERSION))
+    {
+        LLSD version = environment[KEY_ENVVERSION];
+        pinfo->mEnvVersion = version.asInteger();
+    }
+    else
+    {
+        // can be used for region, but versions should be same
+        pinfo->mEnvVersion = pinfo->mIsDefault ? UNSET_PARCEL_ENVIRONMENT_VERSION : INVALID_PARCEL_ENVIRONMENT_VERSION;
+    }
+
     return pinfo;
 }
 
@@ -1746,7 +1773,7 @@ void LLEnvironment::setExperienceEnvironment(LLUUID experience_id, LLUUID asset_
         mPushEnvironmentExpId = experience_id;
         onSetEnvAssetLoaded(ENV_PUSH, asset_id, settings, 
             LLSettingsDay::DEFAULT_DAYLENGTH, LLSettingsDay::DEFAULT_DAYOFFSET, 
-            LLSettingsBase::Seconds(transition_time), status);
+            LLSettingsBase::Seconds(transition_time), status, NO_VERSION);
     });
 
 
diff --git a/indra/newview/llenvironment.h b/indra/newview/llenvironment.h
index 7e35fdcfac..c5ac43704a 100644
--- a/indra/newview/llenvironment.h
+++ b/indra/newview/llenvironment.h
@@ -64,6 +64,8 @@ public:
     static const LLUUID         KNOWN_SKY_MIDNIGHT;
 
     static const S32            NO_TRACK;
+    static const S32            NO_VERSION;
+    static const S32            VERSION_CLEANUP;
 
     struct EnvironmentInfo
     {
@@ -84,6 +86,7 @@ public:
         bool                    mIsLegacy;
         std::string             mDayCycleName;
         namelist_t              mNameList;
+        S32                     mEnvVersion;
 
         static ptr_t            extract(LLSD);
         static ptr_t            extractLegacy(LLSD);
@@ -106,7 +109,7 @@ public:
 
     typedef std::pair<LLSettingsSky::ptr_t, LLSettingsWater::ptr_t> fixedEnvironment_t;
     typedef std::function<void(S32, EnvironmentInfo::ptr_t)>        environment_apply_fn;
-    typedef boost::signals2::signal<void(EnvSelection_t)>           env_changed_signal_t;
+    typedef boost::signals2::signal<void(EnvSelection_t, S32)>           env_changed_signal_t;
     typedef env_changed_signal_t::slot_type                         env_changed_fn;
     typedef std::array<F32, 4>                                      altitude_list_t;
     typedef std::vector<F32>                                        altitudes_vect_t;
@@ -135,14 +138,14 @@ public:
     EnvSelection_t              getSelectedEnvironment() const                  { return mSelectedEnvironment; }
 
     bool                        hasEnvironment(EnvSelection_t env);
-    void                        setEnvironment(EnvSelection_t env, const LLSettingsDay::ptr_t &pday, LLSettingsDay::Seconds daylength, LLSettingsDay::Seconds dayoffset);
-    void                        setEnvironment(EnvSelection_t env, fixedEnvironment_t fixed);
-    void                        setEnvironment(EnvSelection_t env, const LLSettingsBase::ptr_t &fixed); 
-    void                        setEnvironment(EnvSelection_t env, const LLSettingsSky::ptr_t & fixed) { setEnvironment(env, fixedEnvironment_t(fixed, LLSettingsWater::ptr_t())); }
-    void                        setEnvironment(EnvSelection_t env, const LLSettingsWater::ptr_t & fixed) { setEnvironment(env, fixedEnvironment_t(LLSettingsSky::ptr_t(), fixed)); }
-    void                        setEnvironment(EnvSelection_t env, const LLSettingsSky::ptr_t & fixeds, const LLSettingsWater::ptr_t & fixedw) { setEnvironment(env, fixedEnvironment_t(fixeds, fixedw)); }
-    void                        setEnvironment(EnvSelection_t env, const LLUUID &assetId, LLSettingsDay::Seconds daylength, LLSettingsDay::Seconds dayoffset);
-    void                        setEnvironment(EnvSelection_t env, const LLUUID &assetId);
+    void                        setEnvironment(EnvSelection_t env, const LLSettingsDay::ptr_t &pday, LLSettingsDay::Seconds daylength, LLSettingsDay::Seconds dayoffset, S32 env_version = NO_VERSION);
+    void                        setEnvironment(EnvSelection_t env, fixedEnvironment_t fixed, S32 env_version = NO_VERSION);
+    void                        setEnvironment(EnvSelection_t env, const LLSettingsBase::ptr_t &fixed, S32 env_version = NO_VERSION);
+    void                        setEnvironment(EnvSelection_t env, const LLSettingsSky::ptr_t & fixed, S32 env_version = NO_VERSION) { setEnvironment(env, fixedEnvironment_t(fixed, LLSettingsWater::ptr_t()), env_version); }
+    void                        setEnvironment(EnvSelection_t env, const LLSettingsWater::ptr_t & fixed, S32 env_version = NO_VERSION) { setEnvironment(env, fixedEnvironment_t(LLSettingsSky::ptr_t(), fixed), env_version); }
+    void                        setEnvironment(EnvSelection_t env, const LLSettingsSky::ptr_t & fixeds, const LLSettingsWater::ptr_t & fixedw, S32 env_version = NO_VERSION) { setEnvironment(env, fixedEnvironment_t(fixeds, fixedw), env_version); }
+    void                        setEnvironment(EnvSelection_t env, const LLUUID &assetId, LLSettingsDay::Seconds daylength, LLSettingsDay::Seconds dayoffset, S32 env_version = NO_VERSION);
+    void                        setEnvironment(EnvSelection_t env, const LLUUID &assetId, S32 env_version = NO_VERSION);
 
     void                        setSharedEnvironment();
 
@@ -381,7 +384,7 @@ private:
 
     void                        onAgentPositionHasChanged(const LLVector3 &localpos);
 
-    void                        onSetEnvAssetLoaded(EnvSelection_t env, LLUUID asset_id, LLSettingsBase::ptr_t settings, LLSettingsDay::Seconds daylength, LLSettingsDay::Seconds dayoffset, LLSettingsBase::Seconds transition, S32 status);
+    void                        onSetEnvAssetLoaded(EnvSelection_t env, LLUUID asset_id, LLSettingsBase::ptr_t settings, LLSettingsDay::Seconds daylength, LLSettingsDay::Seconds dayoffset, LLSettingsBase::Seconds transition, S32 status, S32 env_version);
     void                        onUpdateParcelAssetLoaded(LLUUID asset_id, LLSettingsBase::ptr_t settings, S32 status, S32 parcel_id, S32 day_length, S32 day_offset, altitudes_vect_t altitudes);
 
     void                        handleEnvironmentPushClear(LLUUID experience_id, LLSD &message, F32 transition);
diff --git a/indra/newview/llfloaterland.cpp b/indra/newview/llfloaterland.cpp
index 25cbf2f576..b20911edc5 100644
--- a/indra/newview/llfloaterland.cpp
+++ b/indra/newview/llfloaterland.cpp
@@ -3281,16 +3281,18 @@ void LLPanelLandEnvironment::refresh()
         setCrossRegion(true);
         mCurrentEnvironment.reset();
         mLastParcelId = INVALID_PARCEL_ID;
+        mCurEnvVersion = INVALID_PARCEL_ENVIRONMENT_VERSION;
         setControlsEnabled(false);
         return;
     }
 
     if (mLastParcelId != getParcelId())
     {
+        mCurEnvVersion = INVALID_PARCEL_ENVIRONMENT_VERSION;
         mCurrentEnvironment.reset();
     }
 
-    if (!mCurrentEnvironment)
+    if (!mCurrentEnvironment && mCurEnvVersion <= INVALID_PARCEL_ENVIRONMENT_VERSION)
     {
         refreshFromSource();
         return;
@@ -3307,6 +3309,7 @@ void LLPanelLandEnvironment::refreshFromSource()
     {
         setNoEnvironmentSupport(true);
         setControlsEnabled(false);
+        mCurEnvVersion = INVALID_PARCEL_ENVIRONMENT_VERSION;
         return;
     }
     setNoEnvironmentSupport(false);
@@ -3315,17 +3318,25 @@ void LLPanelLandEnvironment::refreshFromSource()
     {
         setNoSelection(true);
         setControlsEnabled(false);
+        mCurEnvVersion = INVALID_PARCEL_ENVIRONMENT_VERSION;
         return;
     }
 
     setNoSelection(false);
     if (isSameRegion())
     {
+        LL_DEBUGS("ENVIRONMENT") << "Requesting environment for parcel " << parcel->getLocalID() << ", known version " << mCurEnvVersion << LL_ENDL;
         setCrossRegion(false);
 
         LLHandle<LLPanel> that_h = getHandle();
 
-        mCurEnvVersion = INVALID_PARCEL_ENVIRONMENT_VERSION;
+        if (mCurEnvVersion < UNSET_PARCEL_ENVIRONMENT_VERSION)
+        {
+            // to mark as requesting
+            mCurEnvVersion = parcel->getParcelEnvironmentVersion();
+        }
+        mLastParcelId = parcel->getLocalID();
+
         LLEnvironment::instance().requestParcel(parcel->getLocalID(),
             [that_h](S32 parcel_id, LLEnvironment::EnvironmentInfo::ptr_t envifo) 
             {  
@@ -3340,6 +3351,7 @@ void LLPanelLandEnvironment::refreshFromSource()
         setCrossRegion(true);
         mCurrentEnvironment.reset();
         mLastParcelId = INVALID_PARCEL_ID;
+        mCurEnvVersion = INVALID_PARCEL_ENVIRONMENT_VERSION;
     }
     setControlsEnabled(false);
 }
diff --git a/indra/newview/llfloaterregioninfo.cpp b/indra/newview/llfloaterregioninfo.cpp
index 671f5aca9d..d7d114ca41 100644
--- a/indra/newview/llfloaterregioninfo.cpp
+++ b/indra/newview/llfloaterregioninfo.cpp
@@ -300,8 +300,7 @@ void LLFloaterRegionInfo::onOpen(const LLSD& key)
 		disableTabCtrls();
 		return;
 	}
-	refreshFromRegion(gAgent.getRegion());
-	requestRegionInfo();
+	requestRegionInfo(); // will cause refreshFromRegion()
 	requestMeshRezInfo();
 }
 
@@ -484,6 +483,8 @@ void LLFloaterRegionInfo::processRegionInfo(LLMessageSystem* msg)
 
 	panel->setCtrlsEnabled(allow_modify);
 
+	// Note: region info also causes LLRegionInfoModel::instance().update(msg); -> requestRegion(); -> changed message
+	// we need to know env version here and in update(msg) to know when to request and when not to, when to filter 'changed'
 	floater->refreshFromRegion( gAgent.getRegion() );
 }
 
@@ -3410,7 +3411,10 @@ void LLPanelRegionEnvironment::refresh()
 {
     if (!mCurrentEnvironment)
     {
-        refreshFromSource();
+        if (mCurEnvVersion <= INVALID_PARCEL_ENVIRONMENT_VERSION)
+        {
+            refreshFromSource(); // will immediately set mCurEnvVersion
+        } // else - already requesting
         return;
     }
 
@@ -3426,15 +3430,17 @@ bool LLPanelRegionEnvironment::refreshFromRegion(LLViewerRegion* region)
     {
         setNoSelection(true);
         setControlsEnabled(false);
+        mCurEnvVersion = INVALID_PARCEL_ENVIRONMENT_VERSION;
     }
     setNoSelection(false);
 
     if (gAgent.getRegion()->getRegionID() != region->getRegionID())
     {
         setCrossRegion(true);
+        mCurEnvVersion = INVALID_PARCEL_ENVIRONMENT_VERSION;
     }
     setCrossRegion(false);
-        
+
     refreshFromSource();
     return true;
 }
@@ -3448,9 +3454,15 @@ void LLPanelRegionEnvironment::refreshFromEstate()
 
 void LLPanelRegionEnvironment::refreshFromSource()
 {
+    LL_DEBUGS("ENVIRONMENT") << "Requesting environment for region, known version " << mCurEnvVersion << LL_ENDL;
     LLHandle<LLPanel> that_h = getHandle();
 
-    mCurEnvVersion = INVALID_PARCEL_ENVIRONMENT_VERSION;
+    if (mCurEnvVersion < UNSET_PARCEL_ENVIRONMENT_VERSION)
+    {
+        // to mark as requesting
+        mCurEnvVersion = UNSET_PARCEL_ENVIRONMENT_VERSION;
+    }
+
     LLEnvironment::instance().requestRegion(
         [that_h](S32 parcel_id, LLEnvironment::EnvironmentInfo::ptr_t envifo) { _onEnvironmentReceived(that_h, parcel_id, envifo); });
 
diff --git a/indra/newview/llpanelenvironment.cpp b/indra/newview/llpanelenvironment.cpp
index 8c86e3e8e4..04f281a40c 100644
--- a/indra/newview/llpanelenvironment.cpp
+++ b/indra/newview/llpanelenvironment.cpp
@@ -151,7 +151,7 @@ BOOL LLPanelEnvironmentInfo::postBuild()
 
     getChild<LLMultiSliderCtrl>(SLD_ALTITUDES)->setCommitCallback([this](LLUICtrl *cntrl, const LLSD &value) { onAltSliderCallback(cntrl, value); });
 
-    mChangeMonitor = LLEnvironment::instance().setEnvironmentChanged([this](LLEnvironment::EnvSelection_t env) { onEnvironmentChanged(env); });
+    mChangeMonitor = LLEnvironment::instance().setEnvironmentChanged([this](LLEnvironment::EnvSelection_t env, S32 version) { onEnvironmentChanged(env, version); });
 
     getChild<LLSettingsDropTarget>(SDT_DROP_TARGET)->setPanel(this);
 
@@ -389,7 +389,7 @@ bool LLPanelEnvironmentInfo::setControlsEnabled(bool enabled)
 
     S32 rdo_selection = getChild<LLRadioGroup>(RDG_ENVIRONMENT_SELECT)->getSelectedIndex();
 
-    bool can_enable = enabled && mCurEnvVersion != INVALID_PARCEL_ENVIRONMENT_VERSION;
+    bool can_enable = enabled && mCurrentEnvironment && mCurEnvVersion != INVALID_PARCEL_ENVIRONMENT_VERSION;
     getChild<LLUICtrl>(RDG_ENVIRONMENT_SELECT)->setEnabled(can_enable);
     getChild<LLUICtrl>(RDO_USEDEFAULT)->setEnabled(can_enable && !is_legacy);
     getChild<LLUICtrl>(RDO_USEINV)->setEnabled(false);      // these two are selected automatically based on 
@@ -431,16 +431,16 @@ void LLPanelEnvironmentInfo::setDirtyFlag(U32 flag)
 {
     bool can_edit = canEdit();
     mDirtyFlag |= flag;
-    getChildView(BTN_APPLY)->setEnabled((mDirtyFlag != 0) && mCurEnvVersion != INVALID_PARCEL_ENVIRONMENT_VERSION && can_edit);
-    getChildView(BTN_CANCEL)->setEnabled((mDirtyFlag != 0) && can_edit);
+    getChildView(BTN_APPLY)->setEnabled((mDirtyFlag != 0) && mCurrentEnvironment && mCurEnvVersion != INVALID_PARCEL_ENVIRONMENT_VERSION && can_edit);
+    getChildView(BTN_CANCEL)->setEnabled((mDirtyFlag != 0) && mCurrentEnvironment && can_edit);
 }
 
 void LLPanelEnvironmentInfo::clearDirtyFlag(U32 flag)
 {
     bool can_edit = canEdit();
     mDirtyFlag &= ~flag;
-    getChildView(BTN_APPLY)->setEnabled((mDirtyFlag != 0) && mCurEnvVersion != INVALID_PARCEL_ENVIRONMENT_VERSION && can_edit);
-    getChildView(BTN_CANCEL)->setEnabled((mDirtyFlag != 0) && can_edit);
+    getChildView(BTN_APPLY)->setEnabled((mDirtyFlag != 0) && mCurrentEnvironment && mCurEnvVersion != INVALID_PARCEL_ENVIRONMENT_VERSION && can_edit);
+    getChildView(BTN_CANCEL)->setEnabled((mDirtyFlag != 0) && mCurrentEnvironment && can_edit);
 }
 
 void LLPanelEnvironmentInfo::updateAltLabel(const std::string &alt_name, U32 sky_index, F32 alt_value)
@@ -663,7 +663,6 @@ void LLPanelEnvironmentInfo::doApply()
 
         if (rdo_selection == 0)
         {
-            mCurEnvVersion = INVALID_PARCEL_ENVIRONMENT_VERSION;
             LLEnvironment::instance().resetParcel(parcel_id,
                 [that_h](S32 parcel_id, LLEnvironment::EnvironmentInfo::ptr_t envifo) { _onEnvironmentReceived(that_h, parcel_id, envifo); });
         }
@@ -675,7 +674,6 @@ void LLPanelEnvironmentInfo::doApply()
                 LL_WARNS("ENVPANEL") << "Failed to apply changes from editor! Dirty state: " << mDirtyFlag << " update state: " << mCurEnvVersion << LL_ENDL;
                 return;
             }
-            mCurEnvVersion = INVALID_PARCEL_ENVIRONMENT_VERSION;
             LLEnvironment::instance().updateParcel(parcel_id,
                 mCurrentEnvironment->mDayCycle->getAssetId(), std::string(), mCurrentEnvironment->mDayLength.value(), 
                 mCurrentEnvironment->mDayOffset.value(), alts,
@@ -689,7 +687,6 @@ void LLPanelEnvironmentInfo::doApply()
                 LL_WARNS("ENVPANEL") << "Failed to apply changes from editor! Dirty state: " << mDirtyFlag << " update state: " << mCurEnvVersion << LL_ENDL;
                 return;
             }
-            mCurEnvVersion = INVALID_PARCEL_ENVIRONMENT_VERSION;
             LLEnvironment::instance().updateParcel(parcel_id,
                 mCurrentEnvironment->mDayCycle, mCurrentEnvironment->mDayLength.value(), mCurrentEnvironment->mDayOffset.value(), alts,
                 [that_h](S32 parcel_id, LLEnvironment::EnvironmentInfo::ptr_t envifo) { _onEnvironmentReceived(that_h, parcel_id, envifo); });
@@ -780,36 +777,55 @@ void LLPanelEnvironmentInfo::onEditCommitted(LLSettingsDay::ptr_t newday)
     }
 }
 
-void LLPanelEnvironmentInfo::onEnvironmentChanged(LLEnvironment::EnvSelection_t env)
+void LLPanelEnvironmentInfo::onEnvironmentChanged(LLEnvironment::EnvSelection_t env, S32 new_version)
 {
+    if (new_version < INVALID_PARCEL_ENVIRONMENT_VERSION)
+    {
+        // cleanups and local changes, we are only interested in changes sent by server
+        return;
+    }
+
+    LL_DEBUGS("ENVPANEL") << "Received environment update " << mCurEnvVersion << " " << new_version << LL_ENDL;
+
+    // Environment comes from different sources, from environment update callbacks,
+    // from hovers (causes callbacks on version change) and from personal requests
+    // filter out duplicates and out of order packets by checking parcel environment version.
+
     if (isRegion())
     {
-        // Note: at the moment mCurEnvVersion is only applyable to parcels, we might need separate version control for regions
-        // but mCurEnvVersion still acts like indicator that update is pending
-        if (env == LLEnvironment::ENV_REGION)
+        // Note: region uses same init versions as parcel
+        if (env == LLEnvironment::ENV_REGION
+            // version should be always growing, UNSET_PARCEL_ENVIRONMENT_VERSION is backup case
+            && (mCurEnvVersion < new_version || mCurEnvVersion <= UNSET_PARCEL_ENVIRONMENT_VERSION))
         {
+            if (new_version >= UNSET_PARCEL_ENVIRONMENT_VERSION)
+            {
+                // 'pending state' to prevent re-request on following onEnvironmentChanged if there will be any
+                mCurEnvVersion = new_version;
+            }
             mCurrentEnvironment.reset();
             refreshFromSource();
         }
     }
-    else if ((env == LLEnvironment::ENV_PARCEL) && (getParcelId() == LLViewerParcelMgr::instance().getAgentParcelId()))
+    else if ((env == LLEnvironment::ENV_PARCEL)
+             && (getParcelId() == LLViewerParcelMgr::instance().getAgentParcelId()))
     {
-        // Panel receives environment from different sources, from environment update callbacks,
-        // from hovers (causes callbacks on version change) and from personal requests
-        // filter out dupplicates and out of order packets by checking parcel environment version.
         LLParcel *parcel = getParcel();
         if (parcel)
         {
-            S32 new_version = parcel->getParcelEnvironmentVersion();
-            LL_DEBUGS("ENVPANEL") << "Received environment update " << mCurEnvVersion << " " << new_version << LL_ENDL;
+            // first for parcel own settings, second is for case when parcel uses region settings
             if (mCurEnvVersion < new_version
                 || (mCurEnvVersion != new_version && new_version == UNSET_PARCEL_ENVIRONMENT_VERSION))
             {
+                // 'pending state' to prevent re-request on following onEnvironmentChanged if there will be any
+                mCurEnvVersion = new_version;
                 mCurrentEnvironment.reset();
+
                 refreshFromSource();
             }
-            else
+            else if (mCurrentEnvironment)
             {
+                // update controls
                 refresh();
             }
         }
@@ -839,30 +855,21 @@ void LLPanelEnvironmentInfo::onEnvironmentReceived(S32 parcel_id, LLEnvironment:
     }
     mCurrentEnvironment = envifo;
     clearDirtyFlag(DIRTY_FLAG_MASK);
-    if (parcel_id == INVALID_PARCEL_ID)
+    if (mCurrentEnvironment->mEnvVersion > INVALID_PARCEL_ENVIRONMENT_VERSION)
     {
-        // region, no version
-        // -2 for invalid version viewer -1 for invalid version from server
-        mCurEnvVersion = UNSET_PARCEL_ENVIRONMENT_VERSION;
+        // Server provided version, use it
+        mCurEnvVersion = mCurrentEnvironment->mEnvVersion;
+        LL_DEBUGS("ENVPANEL") << " Setting environment version: " << mCurEnvVersion << " for parcel id: " << parcel_id << LL_ENDL;
     }
+    // Backup: Version was not provided for some reason
     else
     {
-        LLParcel* parcel = getParcel();
-        if (parcel
-            && mCurrentEnvironment->mDayCycle
-            && mCurrentEnvironment->mDayCycle->getAssetId() != LLSettingsDay::GetDefaultAssetId())
-        {
-            // not always up to date, we will get onEnvironmentChanged() update in such case.
-            mCurEnvVersion = parcel->getParcelEnvironmentVersion();
-        }
-        else
-        {
-            // When using 'region' as parcel environment
-            mCurEnvVersion = UNSET_PARCEL_ENVIRONMENT_VERSION;
-        }
-        LL_DEBUGS("ENVPANEL") << " Setting environment version: " << mCurEnvVersion << LL_ENDL;
+        LL_WARNS("ENVPANEL") << " Environment version was not provided for " << parcel_id << ", old env version: " << mCurEnvVersion << LL_ENDL;
     }
+
     refresh();
+
+    // todo: we have envifo and parcel env version, should we just setEnvironment() and parcel's property to prevent dupplicate requests?
 }
 
 void LLPanelEnvironmentInfo::_onEnvironmentReceived(LLHandle<LLPanel> that_h, S32 parcel_id, LLEnvironment::EnvironmentInfo::ptr_t envifo)
diff --git a/indra/newview/llpanelenvironment.h b/indra/newview/llpanelenvironment.h
index bca7743145..05f25fa78f 100644
--- a/indra/newview/llpanelenvironment.h
+++ b/indra/newview/llpanelenvironment.h
@@ -142,7 +142,7 @@ protected:
 
     LLEnvironment::EnvironmentInfo::ptr_t   mCurrentEnvironment;
 
-    void                        onEnvironmentChanged(LLEnvironment::EnvSelection_t env);
+    void                        onEnvironmentChanged(LLEnvironment::EnvSelection_t env, S32 version);
 
     class AltitudeData
     {
@@ -160,7 +160,7 @@ protected:
     };
     typedef std::map<std::string, AltitudeData>      altitudes_data_t;
     altitudes_data_t                        mAltitudes;
-    S32                                     mCurEnvVersion;
+    S32                                     mCurEnvVersion; // used to filter duplicate callbacks/refreshes
 
 
 private: