diff --git a/.gitignore b/.gitignore
index 4f4dac5..e238904 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,14 +4,23 @@ NOTES.md
 MARKETPLACE.md
 optimized
 
-# Compressed/optimized LSL scripts
+# Release
+AVsitter2/AVsitter2.zip
+AVsitter2/AVsitter2-oss.zip
+
+# Compressed/optimized/processed LSL scripts
 *.lslz
+*.lslo
+*.oss
 
 .project
 .buildpath
 .settings
 .externalToolBuilders
 
+# Linux backup files
+*~
+
 # Windows image file caches
 Thumbs.db
 ehthumbs.db
diff --git a/AVsitter2/Makefile b/AVsitter2/Makefile
new file mode 100644
index 0000000..f42c5e8
--- /dev/null
+++ b/AVsitter2/Makefile
@@ -0,0 +1,87 @@
+# Configuration area
+
+# Full path to Python. For Windows this is typically
+# C:\Python27\python.exe; if it is in your path you don't need to change it.
+PYTHON=python
+
+# Full path to main.py in the optimizer. Depends on where it was unpacked.
+OPTIMIZER=/l/pyoptimizer/main.py
+
+# Which preprocessor to use. Use 'gcpp' for GNU cpp (typical on Linux);
+# use 'mcpp' for mcpp.
+PREPROC_KIND=mcpp
+
+# Full path to the preprocessor. Depends on where you have downloaded it.
+# If the preprocessor is mcpp and it is in your path, you can leave it as is.
+PREPROC_PATH=mcpp
+
+# Command to remove files in your system. Use 'del' for Windows.
+RM=rm -f
+
+# Name of the zipped file to generate for SL
+SLZIP=AVsitter2.zip
+
+# Name of the zipped file to generate for OpenSim
+OSZIP=AVsitter2-oss.zip
+
+# End of configuration area
+
+
+
+# Note some of these scripts don't strictly need to be optimized for memory.
+
+OPTIMIZED=[AV]sitA.lslo\
+ [AV]sitB.lslo\
+ [AV]adjuster.lslo\
+ [AV]helper.lslo\
+ [AV]root-security.lslo\
+ [AV]root.lslo\
+ [AV]select.lslo\
+ Plugins/AVcamera/[AV]camera.lslo\
+ Plugins/AVcontrol/Xcite!-Sensations/[AV]Xcite!.lslo\
+ Plugins/AVcontrol/[AV]root-RLV-extra.lslo\
+ Plugins/AVcontrol/[AV]root-RLV.lslo\
+ Plugins/AVcontrol/[AV]root-control.lslo\
+ Plugins/AVfaces/[AV]faces.lslo\
+ Plugins/AVprop/[AV]menu.lslo\
+ Plugins/AVprop/[AV]prop.lslo\
+ Plugins/AVprop/[AV]object.lslo\
+ Plugins/AVsequence/[AV]sequence.lslo\
+ Utilities/AVpos-generator.lslo\
+ Utilities/AVpos-shifter.lslo\
+ Utilities/Anim-perm-checker.lslo\
+ Utilities/MLP-converter.lslo\
+ Utilities/Missing-anim-finder.lslo
+
+UNOPTIMIZED=Plugins/AVcontrol/LockGuard/[AV]LockGuard.lsl\
+ Plugins/AVcontrol/LockGuard/[AV]LockGuard-object.lsl
+
+OPENSIM=[AV]sitA.oss\
+ [AV]sitB.oss\
+ [AV]adjuster.oss\
+ [AV]helper.oss
+
+all: $(SLZIP) $(OSZIP)
+
+clean:
+	$(RM) $(SLZIP) $(OSZIP) $(OPTIMIZED) $(OPENSIM)
+
+optimized: $(OPTIMIZED)
+
+opensim: $(OPENSIM)
+
+$(SLZIP): $(OPTIMIZED) $(UNOPTIMIZED)
+	$(RM) $@
+	zip $@ $(OPTIMIZED) $(UNOPTIMIZED)
+
+%.lslo: %.lsl
+	$(PYTHON) $(OPTIMIZER) -H -O addstrings,shrinknames,-extendedglobalexpr -p $(PREPROC_KIND) --precmd=$(PREPROC_PATH) $< -o $@
+
+$(OSZIP): $(OPENSIM)
+	$(RM) $@
+	zip $@ $(OPENSIM)
+
+%.oss: %.lsl
+	$(PYTHON) prepare-for-oss.py $< > $@
+
+.PHONY : all clean optimized
diff --git a/AVsitter2/Plugins/AVcamera/[AV]camera.lsl b/AVsitter2/Plugins/AVcamera/[AV]camera.lsl
index 56b422c..78ed35a 100644
--- a/AVsitter2/Plugins/AVcamera/[AV]camera.lsl
+++ b/AVsitter2/Plugins/AVcamera/[AV]camera.lsl
@@ -55,7 +55,7 @@ Readout_Say(string say, string SCRIPT_CHANNEL)
 
 set_camera(integer byButton)
 {
-    if (mySitter)
+    if (mySitter) // OSS::if (osIsUUID(mySitter) && mySitter != NULL_KEY)
     {
         if (llGetPermissions() & PERMISSION_CONTROL_CAMERA)
         {
diff --git a/AVsitter2/Plugins/AVcontrol/[AV]root-RLV-extra.lsl b/AVsitter2/Plugins/AVcontrol/[AV]root-RLV-extra.lsl
index 0f96ed4..b157e04 100644
--- a/AVsitter2/Plugins/AVcontrol/[AV]root-RLV-extra.lsl
+++ b/AVsitter2/Plugins/AVcontrol/[AV]root-RLV-extra.lsl
@@ -297,14 +297,14 @@ state running
                 integer i;
                 for (i = 0; i < llGetListLength(CLOTHING_LAYERS); i++)
                 {
-                    if (llList2String(CLOTHING_LAYERS, i))
+                    if (llList2String(CLOTHING_LAYERS, i) != "")
                     {
                         relay(SLAVE, "@remoutfit:" + llList2String(CLOTHING_LAYERS, i) + "=force");
                     }
                 }
                 for (i = 0; i < llGetListLength(ATTACHMENT_POINTS); i++)
                 {
-                    if (llList2String(ATTACHMENT_POINTS, i))
+                    if (llList2String(ATTACHMENT_POINTS, i) != "")
                     {
                         if (i != 2)
                         {
diff --git a/AVsitter2/Plugins/AVcontrol/[AV]root-RLV.lsl b/AVsitter2/Plugins/AVcontrol/[AV]root-RLV.lsl
index d2fd92b..8ed707f 100644
--- a/AVsitter2/Plugins/AVcontrol/[AV]root-RLV.lsl
+++ b/AVsitter2/Plugins/AVcontrol/[AV]root-RLV.lsl
@@ -183,7 +183,7 @@ relay_select_menu()
 
 playpose(string pose, string target_sitter)
 {
-    if (pose)
+    if (pose != "")
     {
         llSleep(1);
         llMessageLinked(LINK_SET, 90000, pose, target_sitter);
@@ -289,7 +289,7 @@ reset()
 unsit_all()
 {
     integer i = llGetNumberOfPrims();
-    while (llGetAgentSize(llGetLinkKey(i)))
+    while (llGetAgentSize(llGetLinkKey(i)) != ZERO_VECTOR)
     {
         llUnSit(llGetLinkKey(i));
         i--;
@@ -401,7 +401,7 @@ select_submissive_rlv()
     {
         if (llList2String(SITTER_DESIGNATIONS_MASTER, i) == "S")
         {
-            if (llList2Key(DESIGNATIONS_NOW, i))
+            if (llList2Key(DESIGNATIONS_NOW, i)) // OSS::key k = llList2Key(DESIGNATIONS_NOW, i); if (osIsUUID(k) && k != NULL_KEY)
             {
                 menu_items += llGetSubString(strReplace(llKey2Name(llList2Key(DESIGNATIONS_NOW, i)), " Resident", ""), 0, 11);
                 SITTERS_MENUKEYS += llList2Key(DESIGNATIONS_NOW, i);
@@ -635,7 +635,7 @@ state running
                 {
                     release_all();
                 }
-                if (des1)
+                if (des1) // OSS::if (osIsUUID(des1) && des1 != NULL_KEY)
                 {
                     DESIGNATIONS_NOW = llListReplaceList(DESIGNATIONS_NOW, [des1], two, two);
                 }
@@ -643,7 +643,7 @@ state running
                 {
                     DESIGNATIONS_NOW = llListReplaceList(DESIGNATIONS_NOW, [role2], two, two);
                 }
-                if (des2)
+                if (des2) // OSS::if (osIsUUID(des2) && des2 != NULL_KEY)
                 {
                     DESIGNATIONS_NOW = llListReplaceList(DESIGNATIONS_NOW, [des2], one, one);
                 }
@@ -895,7 +895,7 @@ state running
                     {
                         if (~llListFindList(DESIGNATIONS_NOW, ["S"]))
                         {
-                            if (CONTROLLER)
+                            if (CONTROLLER) // OSS::if (osIsUUID(CONTROLLER) && CONTROLLER != NULL_KEY)
                             {
                                 PairWhoStartedCapture = (string)CONTROLLER + (string)llGetOwnerKey(id);
                             }
@@ -935,7 +935,7 @@ state running
             }
             else if (msg == "[BACK]")
             {
-                if (menu)
+                if (menu != "")
                 {
                     rlv_top_menu();
                 }
diff --git a/AVsitter2/Plugins/AVfaces/[AV]faces.lsl b/AVsitter2/Plugins/AVfaces/[AV]faces.lsl
index 3c126fb..69e0749 100644
--- a/AVsitter2/Plugins/AVfaces/[AV]faces.lsl
+++ b/AVsitter2/Plugins/AVfaces/[AV]faces.lsl
@@ -155,7 +155,7 @@ sequence()
             {
                 anim = llStringTrim(llList2String(sequence_anims, j - 1), STRING_TRIM);
             }
-            if (anim)
+            if (anim != "")
             {
                 if (IsInteger(anim))
                 {
@@ -204,7 +204,7 @@ remove_sequences(key id)
         list sequence = llParseStringKeepNulls(llList2String(anim_animsequences, llList2Integer(running_sequence_indexes, index)), ["|"], []);
         running_sequence_indexes = llDeleteSubList(running_sequence_indexes, index, index);
         running_pointers = llDeleteSubList(running_pointers, index, index);
-        while (sequence)
+        while (sequence != [])
         {
             if (!IsInteger(llList2String(sequence, 0)) && llList2String(sequence, 0) != "none")
             {
diff --git a/AVsitter2/Plugins/AVprop/[AV]menu.lsl b/AVsitter2/Plugins/AVprop/[AV]menu.lsl
index dd63dc4..7bb5fcd 100644
--- a/AVsitter2/Plugins/AVprop/[AV]menu.lsl
+++ b/AVsitter2/Plugins/AVprop/[AV]menu.lsl
@@ -323,7 +323,7 @@ default
 
     listen(integer listen_channel, string name, key id, string msg)
     {
-        if (choice)
+        if (choice != "")
         {
             if (msg == "")
             {
@@ -376,11 +376,11 @@ default
         if (mindex_test != -1)
         {
             list button_data = llParseStringKeepNulls(llList2String(DATA_LIST, mindex_test), ["�"], []);
-            if (llList2String(button_data, 1))
+            if (llList2String(button_data, 1) != "")
             {
                 msg = llList2String(button_data, 1);
             }
-            if (llList2String(button_data, 2))
+            if (llList2String(button_data, 2) != "")
             {
                 id = llList2String(button_data, 2);
             }
@@ -447,7 +447,7 @@ default
             Readout_Say("");
             Readout_Say("--✄--COPY BELOW INTO \"AVpos\" NOTECARD--✄--");
             Readout_Say("");
-            if (custom_text)
+            if (custom_text != "")
             {
                 Readout_Say("TEXT " + strReplace(custom_text, "\n", "\\n"));
             }
diff --git a/AVsitter2/Plugins/AVprop/[AV]object.lsl b/AVsitter2/Plugins/AVprop/[AV]object.lsl
index 15f6f20..a4741e1 100644
--- a/AVsitter2/Plugins/AVprop/[AV]object.lsl
+++ b/AVsitter2/Plugins/AVprop/[AV]object.lsl
@@ -27,7 +27,7 @@ key give_prop_warning_request;
 unsit_all()
 {
     integer i = llGetNumberOfPrims();
-    while (llGetAgentSize(llGetLinkKey(i)))
+    while (llGetAgentSize(llGetLinkKey(i)) != ZERO_VECTOR)
     {
         llUnSit(llGetLinkKey(i));
         i--;
@@ -83,7 +83,7 @@ state prop
         {
             if (llGetInventoryType("[AV]sitA") == INVENTORY_NONE)
             {
-                llSetClickAction(-1);
+                llSetClickAction(-1); // OSS::llSetClickAction(CLICK_ACTION_DEFAULT);
             }
         }
         else
@@ -231,7 +231,7 @@ state prop
                 }
                 else
                 {
-                    if (llGetAgentSize(llGetLinkKey(llGetNumberOfPrims())))
+                    if (llGetAgentSize(llGetLinkKey(llGetNumberOfPrims())) != ZERO_VECTOR)
                     {
                         unsit_all();
                         llSleep(1);
diff --git a/AVsitter2/Plugins/AVprop/[AV]prop.lsl b/AVsitter2/Plugins/AVprop/[AV]prop.lsl
index 40841cc..e157c42 100644
--- a/AVsitter2/Plugins/AVprop/[AV]prop.lsl
+++ b/AVsitter2/Plugins/AVprop/[AV]prop.lsl
@@ -223,7 +223,7 @@ remove_props_by_sitter(string sitter, integer remove_type3)
     {
         command = "REM_WORLD";
     }
-    if (text)
+    if (text != [])
     {
         send_command(llDumpList2String([command] + text, "|"));
     }
@@ -248,7 +248,7 @@ remove_sitter_props_by_pose(string sitter_pose, integer remove_type3)
             }
         }
     }
-    if (text)
+    if (text != [])
     {
         send_command(llDumpList2String(["REM_INDEX"] + text, "|"));
     }
@@ -286,7 +286,7 @@ remove_props_by_group(integer gp)
     {
         command = "REM_WORLD";
     }
-    if (text)
+    if (text != [])
     {
         send_command(llDumpList2String([command] + text, "|"));
     }
@@ -413,7 +413,7 @@ default
                         }
                     }
                 }
-                if (sitting_av_or_sitter)
+                if (sitting_av_or_sitter) // OSS::if (osIsUUID(sitting_av_or_sitter) && sitting_av_or_sitter != NULL_KEY)
                 {
                     if (num == 90200) // send menu back?
                     {
diff --git a/AVsitter2/Plugins/AVsequence/[AV]sequence.lsl b/AVsitter2/Plugins/AVsequence/[AV]sequence.lsl
index cc37ede..b1582b0 100644
--- a/AVsitter2/Plugins/AVsequence/[AV]sequence.lsl
+++ b/AVsitter2/Plugins/AVsequence/[AV]sequence.lsl
@@ -275,7 +275,7 @@ default
                 }
                 else if (command == "SEQUENCE")
                 {
-                    if (CURRENT_SEQUENCE_NAME)
+                    if (CURRENT_SEQUENCE_NAME != "")
                     {
                         commit_sequence_data();
                     }
diff --git a/AVsitter2/RELEASE.md b/AVsitter2/RELEASE.md
new file mode 100644
index 0000000..d5ca594
--- /dev/null
+++ b/AVsitter2/RELEASE.md
@@ -0,0 +1,41 @@
+# Creating a release version
+
+## Needed tools
+
+To create a release version like the ones available for download, you need to have the following tools:
+
+### For Linux
+
+- **zip**. It comes in most distributions, e.g. for Debian or Ubuntu use `sudo apt-get install zip`; if it isn't available in yours, try this link: <http://www.info-zip.org/Zip.html#Downloads>
+- **Python 2.7**. It comes in most distributions, e.g. for Debian or Ubuntu use `sudo apt-get install python`; if it isn't available in yours, try this link: <https://www.python.org/downloads/>. **Important:** Python 3.x won't work; only Python 2.x will. Usually Python 2 and Python 3 can be installed side-by-side.
+- **make**. It comes in most distributions, e.g. for Debian or Ubuntu use `sudo apt-get install make`; if it isn't available in yours, try this link: <https://www.gnu.org/software/make/#download>
+- **GNU cpp**. It comes in most distributions, e.g. for Debian or Ubuntu use `sudo apt-get install cpp`. If it isn't available in yours, or you have trouble installing it, you can instead use **mcpp**, which is much more lightweight and is included in most distributions. It is also available at this link: <http://mcpp.sourceforge.net/download.html>.
+- [**LSL-PyOptimizer**](https://github.com/Sei-Lisa/LSL-PyOptimizer). Currently the latest master branch is used to create the releases, which you can download by clicking on "Clone or Download" in the top right of the linked page.
+
+### For Mac OS/X
+
+- **zip** (comes preinstalled)
+- **Python 2.7** (comes preinstalled) **Important:** Python 3.x won't work; only Python 2.x will.
+- **make** - It comes as part of **Xcode** which you can get for free from the App Store.
+- [**mcpp**](http://mcpp.sourceforge.net/download.html). There's a DMG for download.
+- [**LSL-PyOptimizer**](https://github.com/Sei-Lisa/LSL-PyOptimizer). Currently the latest master branch is used to create the releases, which you can download by clicking on "Clone or Download" in the top right of the linked page.
+
+### For Windows
+
+- [**zip**](http://www.info-zip.org/Zip.html#Downloads)
+- [**Python 2.7**](https://www.python.org/downloads/) **Important:** Python 3.x won't work; only Python 2.x will.
+- [**make**](http://gnuwin32.sourceforge.net/packages/make.htm#download)
+- [**mcpp**](http://mcpp.sourceforge.net/download.html)
+- [**LSL-PyOptimizer**](https://github.com/Sei-Lisa/LSL-PyOptimizer). Currently the latest master branch is used to create the releases, which you can download by clicking on "Clone or Download" in the top right of the linked page.
+
+## Creating the release
+
+Once you have the required tools, edit the Makefile in the AVsitter2 folder to suit your needs, then using a terminal (also called command interpreter, shell, console... depending on the operating system) change to that folder using `cd <path-to-folder>` and type `make`. That should generate a file called `AVsitter2.zip` with the packaged version for SL, and another file called `AVsitter2-oss.zip` with the packaged version for OpenSim.
+
+If you only want the Second Life optimized scripts without zipping them, use `make optimized`. The optimized files will have an `.lslo` extension, and they are ready to be copied and pasted each into a Second Life script.
+
+If you only want the OpenSim scripts without zipping them, use `make opensim`. The OpenSim files will have an `.oss` extension.
+
+If you only want the SL zip, use `make AVsitter2.zip`; if you only want the OS zip, use `make AVsitter2-oss.zip`.
+
+If you want to remove the optimized scripts and the zip files, use `make clean` (you can regenerate them at any time by typing `make`).
diff --git a/AVsitter2/Utilities/AVpos-shifter.lsl b/AVsitter2/Utilities/AVpos-shifter.lsl
index f0c106f..5d7269c 100644
--- a/AVsitter2/Utilities/AVpos-shifter.lsl
+++ b/AVsitter2/Utilities/AVpos-shifter.lsl
@@ -46,7 +46,7 @@ integer IsVector(string s)
 
 string FormatFloat(float f, integer num_decimals)
 {
-    float rounding = (float)(".5e-" + (string)num_decimals) - 5e-07;
+    float rounding = (float)(".5e-" + (string)num_decimals) - .5e-6;
     if (f < 0.)
         f -= rounding;
     else
diff --git a/AVsitter2/Utilities/MLP-converter.lsl b/AVsitter2/Utilities/MLP-converter.lsl
index e471c0f..2c2a60e 100644
--- a/AVsitter2/Utilities/MLP-converter.lsl
+++ b/AVsitter2/Utilities/MLP-converter.lsl
@@ -36,7 +36,7 @@ Out(integer level, string out)
 
 string FormatFloat(float f, integer num_decimals)
 {
-    float rounding = (float)(".5e-" + (string)num_decimals) - 5e-07;
+    float rounding = (float)(".5e-" + (string)num_decimals) - .5e-6;
     if (f < 0.)
         f -= rounding;
     else
diff --git a/AVsitter2/[AV]adjuster.lsl b/AVsitter2/[AV]adjuster.lsl
index 8282c9d..f50cd1e 100644
--- a/AVsitter2/[AV]adjuster.lsl
+++ b/AVsitter2/[AV]adjuster.lsl
@@ -49,7 +49,7 @@ integer webcount;
 
 string FormatFloat(float f, integer num_decimals)
 {
-    float rounding = (float)(".5e-" + (string)num_decimals) - 5e-07;
+    float rounding = (float)(".5e-" + (string)num_decimals) - .5e-6;
     if (f < 0.)
         f -= rounding;
     else
@@ -112,12 +112,12 @@ list order_buttons(list buttons)
 
 string strReplace(string str, string search, string replace)
 {
-    return llDumpList2String(llParseStringKeepNulls(str, [search], []), replace);
+    return llDumpList2String(llParseStringKeepNulls(str, [search], []), replace); // OSS::return osReplaceString(str, search, replace, -1, 0);
 }
 
 preview_anim(string anim, key id)
 {
-    if (id)
+    if (id) // OSS::if (osIsUUID(id) && id != NULL_KEY)
     {
         stop_all_anims(id);
         llMessageLinked(LINK_THIS, 90001, anim, id);
@@ -311,7 +311,7 @@ camera_menu()
 unsit_all()
 {
     integer i = llGetNumberOfPrims();
-    while (llGetAgentSize(llGetLinkKey(i)))
+    while (llGetAgentSize(llGetLinkKey(i)) != ZERO_VECTOR)
     {
         stop_all_anims(llGetLinkKey(i));
         llUnSit(llGetLinkKey(i));
@@ -471,11 +471,11 @@ default
                         {
                             Readout_Say("SWAP " + llList2String(data, 4));
                         }
-                        if (llList2String(data, 6))
+                        if (llList2String(data, 6) != "")
                         {
                             Readout_Say("TEXT " + strReplace(llList2String(data, 6), "\n", "\\n"));
                         }
-                        if (llList2String(data, 7))
+                        if (llList2String(data, 7) != "")
                         {
                             Readout_Say("ADJUST " + strReplace(llList2String(data, 7), "�", "|"));
                         }
@@ -496,7 +496,7 @@ default
                     if (llGetListLength(SITTERS) > 1 || llList2String(data, 5) != "")
                     {
                         string SITTER_TEXT;
-                        if (llList2String(data, 5))
+                        if (llList2String(data, 5) != "")
                         {
                             SITTER_TEXT = "|" + strReplace(llList2String(data, 5), "�", "|");
                         }
@@ -574,7 +574,7 @@ default
                     integer i;
                     for (i = 0; i < llGetListLength(SITTERS); i++)
                     {
-                        if (llList2String(SITTER_POSES, i))
+                        if (llList2String(SITTER_POSES, i) != "")
                         {
                             string type = "SYNC";
                             string temp_pose_name = llList2String(SITTER_POSES, i);
@@ -622,7 +622,7 @@ default
         {
             if (OLD_HELPER_METHOD)
             {
-                if (llGetAgentSize(llGetLinkKey(llGetNumberOfPrims())))
+                if (llGetAgentSize(llGetLinkKey(llGetNumberOfPrims())) != ZERO_VECTOR)
                 {
                     end_helper_mode();
                 }
diff --git a/AVsitter2/[AV]helper.lsl b/AVsitter2/[AV]helper.lsl
index a4b1847..fd83d1b 100644
--- a/AVsitter2/[AV]helper.lsl
+++ b/AVsitter2/[AV]helper.lsl
@@ -31,11 +31,11 @@ rotation my_rot;
 
 stop_all_anims()
 {
-    if (llAvatarOnSitTarget())
+    if (llAvatarOnSitTarget()) // OSS::if (llAvatarOnSitTarget() != NULL_KEY)
     {
         if (llGetPermissions() & PERMISSION_TRIGGER_ANIMATION)
         {
-            if (llGetAgentSize(llGetPermissionsKey()))
+            if (llGetAgentSize(llGetPermissionsKey()) != ZERO_VECTOR)
             {
                 list anims = llGetAnimationList(llGetPermissionsKey());
                 integer n;
@@ -148,9 +148,9 @@ default
         if (chan == 5 && id == CURRENT_AV)
         {
             key av = (key)msg;
-            if (av)
+            if (av) // OSS::if (osIsUUID(av) && av != NULL_KEY)
             {
-                if (llGetAgentSize(av))
+                if (llGetAgentSize(av) != ZERO_VECTOR)
                 {
                     list avatar_location = llGetObjectDetails(av, [OBJECT_POS, OBJECT_ROT]);
                     if (llVecMag(llGetPos() - llList2Vector(avatar_location, 0)) < 10)
@@ -175,7 +175,7 @@ default
             {
                 if (OLD_HELPER_METHOD)
                 {
-                    if (llAvatarOnSitTarget())
+                    if (llAvatarOnSitTarget()) // OSS::if (llAvatarOnSitTarget() != NULL_KEY)
                     {
                         stop_all_anims();
                         llRegionSay(comm_channel, "GETUP");
@@ -244,7 +244,7 @@ default
             key av = llAvatarOnSitTarget();
             if (OLD_HELPER_METHOD)
             {
-                if (av)
+                if (av) // OSS::if (osIsUUID(av) && av != NULL_KEY)
                 {
                     llRequestPermissions(av, PERMISSION_TRIGGER_ANIMATION);
                     llRegionSay(comm_channel, "ANIMA|" + (string)av);
@@ -256,7 +256,7 @@ default
                     CURRENT_AV = "";
                 }
             }
-            else if (av)
+            else if (av) // OSS::if (osIsUUID(av) && av != NULL_KEY)
             {
                 llUnSit(av);
                 llDialog(av, product + " " + version + "\n\nDo not sit on the helper with AVsitter2 unless you have enabled the old helper mode. Move the helper while sitting on the furniture. Please see instructions at http://avsitter.com", ["OK"], -68154283);
diff --git a/AVsitter2/[AV]sitA.lsl b/AVsitter2/[AV]sitA.lsl
index b34c4ae..de0c34b 100644
--- a/AVsitter2/[AV]sitA.lsl
+++ b/AVsitter2/[AV]sitA.lsl
@@ -107,7 +107,7 @@ integer get_number_of_scripts()
 dialog(string text, list menu_items)
 {
     llListenRemove(menu_handle);
-    menu_handle = llListen(menu_channel = ((integer)llFrand(0x7FFFFF80) + 1) * -1, "", CONTROLLER, ""); // 7FFFFF80 = max float < 2^31
+    menu_handle = llListen((menu_channel = ((integer)llFrand(0x7FFFFF80) + 1) * -1), "", CONTROLLER, ""); // 7FFFFF80 = max float < 2^31
     llDialog(CONTROLLER, product + " " + version + "\n\n" + text, order_buttons(menu_items), menu_channel);
 }
 
@@ -262,7 +262,7 @@ release_sitter(integer i)
     {
         if (llGetPermissions() & PERMISSION_TRIGGER_ANIMATION)
         {
-            if (MY_SITTER)
+            if (MY_SITTER) // OSS::if (osIsUUID(MY_SITTER) && MY_SITTER != NULL_KEY)
             {
                 llMessageLinked(LINK_SET, 90065, (string)SCRIPT_CHANNEL, MY_SITTER); // 90065=sitter gone
             }
@@ -340,7 +340,7 @@ apply_current_anim(integer broadcast)
     }
     if (llGetPermissions() & PERMISSION_TRIGGER_ANIMATION)
     {
-        if (llGetAgentSize(MY_SITTER))
+        if (llGetAgentSize(MY_SITTER) != ZERO_VECTOR)
         {
             if (broadcast)
             {
@@ -368,7 +368,7 @@ apply_current_anim(integer broadcast)
             {
                 sit_using_prim_params();
             }
-            if (CURRENT_ANIMATION_FILENAME)
+            if (CURRENT_ANIMATION_FILENAME != "")
             {
                 llStartAnimation(CURRENT_ANIMATION_FILENAME);
             }
@@ -388,7 +388,7 @@ apply_current_anim(integer broadcast)
 sit_using_prim_params()
 {
     integer sitter_prim = llGetNumberOfPrims();
-    while (llGetAgentSize(llGetLinkKey(sitter_prim)))
+    while (llGetAgentSize(llGetLinkKey(sitter_prim)) != ZERO_VECTOR)
     {
         if (llGetLinkKey(sitter_prim) == MY_SITTER)
         {
@@ -425,9 +425,9 @@ sit_using_prim_params()
 end_sitter()
 {
     llSetTimerEvent(0);
-    if (MY_SITTER)
+    if (MY_SITTER) // OSS::if (osIsUUID(MY_SITTER) && MY_SITTER != NULL_KEY)
     {
-        if (CURRENT_ANIMATION_FILENAME)
+        if (CURRENT_ANIMATION_FILENAME != "")
         {
             llStopAnimation(CURRENT_ANIMATION_FILENAME);
         }
@@ -485,9 +485,9 @@ default
         update_current_anim_name();
         if (llGetPermissions() & PERMISSION_TRIGGER_ANIMATION)
         {
-            if (llGetAgentSize(MY_SITTER))
+            if (llGetAgentSize(MY_SITTER) != ZERO_VECTOR)
             {
-                if (CURRENT_ANIMATION_FILENAME)
+                if (CURRENT_ANIMATION_FILENAME != "")
                 {
                     llStartAnimation(CURRENT_ANIMATION_FILENAME);
                 }
@@ -657,7 +657,7 @@ default
                 {
                     reused_key = llList2Key(SITTERS, two);
                 }
-                if (reused_key)
+                if (reused_key) // OSS::if (osIsUUID(reused_key) && reused_key != NULL_KEY)
                 {
                     SWAPPED = TRUE;
                     llRequestPermissions(reused_key, PERMISSION_TRIGGER_ANIMATION);
@@ -833,7 +833,7 @@ default
                         {
                             if (sitterGender)
                             {
-                                if (MALE_POSENAME)
+                                if (MALE_POSENAME != "")
                                 {
                                     if (CURRENT_POSE_NAME == FIRST_POSENAME)
                                     {
@@ -844,7 +844,7 @@ default
                             }
                             else
                             {
-                                if (FEMALE_POSENAME)
+                                if (FEMALE_POSENAME != "")
                                 {
                                     if (CURRENT_POSE_NAME == FIRST_POSENAME)
                                     {
@@ -875,7 +875,7 @@ default
                         {
                             if (llGetPermissions() & PERMISSION_TRIGGER_ANIMATION)
                             {
-                                if (MY_SITTER)
+                                if (MY_SITTER) // OSS::if (osIsUUID(MY_SITTER) && MY_SITTER != NULL_KEY)
                                 {
                                     llMessageLinked(LINK_SET, 90065, (string)SCRIPT_CHANNEL, MY_SITTER); // 90065=sitter gone
                                 }
@@ -900,7 +900,7 @@ default
                     {
                         actual_sitter = llAvatarOnSitTarget();
                     }
-                    if (existing_sitter)
+                    if (existing_sitter != "")
                     {
                         if (actual_sitter == NULL_KEY)
                         {
@@ -909,13 +909,13 @@ default
                             release_sitter(i);
                         }
                     }
-                    else if (actual_sitter)
+                    else if (actual_sitter) // OSS::else if (osIsUUID(actual_sitter) && actual_sitter != NULL_KEY)
                     {
                         if (i == SCRIPT_CHANNEL)
                         {
                             if (llList2Integer(llGetObjectDetails(actual_sitter, [OBJECT_BODY_SHAPE_TYPE]), 0))
                             {
-                                if (MALE_POSENAME)
+                                if (MALE_POSENAME != "")
                                 {
                                     if (CURRENT_POSE_NAME == FIRST_POSENAME)
                                     {
@@ -926,7 +926,7 @@ default
                             }
                             else
                             {
-                                if (FEMALE_POSENAME)
+                                if (FEMALE_POSENAME != "")
                                 {
                                     if (CURRENT_POSE_NAME == FIRST_POSENAME)
                                     {
@@ -994,7 +994,7 @@ default
                 animation_menu_function = -1;
             }
             reused_key = "";
-            SITTERS = llListReplaceList(SITTERS, [CONTROLLER = MY_SITTER = llGetPermissionsKey()], SCRIPT_CHANNEL, SCRIPT_CHANNEL);
+            SITTERS = llListReplaceList(SITTERS, [(CONTROLLER = MY_SITTER = llGetPermissionsKey())], SCRIPT_CHANNEL, SCRIPT_CHANNEL);
             string channel_or_swap = (string)SCRIPT_CHANNEL;
             integer lnk = 90000; // 90000=play pose
             if (SWAPPED)
diff --git a/AVsitter2/[AV]sitB.lsl b/AVsitter2/[AV]sitB.lsl
index 9433269..f6985fa 100644
--- a/AVsitter2/[AV]sitB.lsl
+++ b/AVsitter2/[AV]sitB.lsl
@@ -86,18 +86,18 @@ integer animation_menu(integer animation_menu_function)
     else
     {
         string menu = product + version;
-        if (BRAND)
+        if (BRAND != "")
             menu = BRAND;
         if (CONTROLLER != MY_SITTER || has_RLV)
         {
             menu += "\n\nMenu for " + llKey2Name(MY_SITTER);
         }
         menu += "\n\n";
-        if (CUSTOM_TEXT)
+        if (CUSTOM_TEXT != "")
         {
             menu += CUSTOM_TEXT + "\n";
         }
-        if (SITTER_INFO)
+        if (SITTER_INFO != "")
         {
             menu += "[" + llList2String(llParseStringKeepNulls(SITTER_INFO, ["�"], []), 0) + "]";
         }
@@ -149,7 +149,7 @@ integer animation_menu(integer animation_menu_function)
         if (helper_mode)
         {
             menu_items2 += "[NEW]";
-            if (CURRENT_POSE_NAME)
+            if (CURRENT_POSE_NAME != "")
             {
                 menu_items2 += "[DUMP]";
                 menu_items2 += "[SAVE]";
@@ -189,7 +189,7 @@ integer animation_menu(integer animation_menu_function)
             items_per_page -= 2;
         }
         list menu_items1;
-        integer page_start = i = current_menu + 1 + menu_page * items_per_page;
+        integer page_start = (i = current_menu + 1 + menu_page * items_per_page);
         do
         {
             if (i < llGetListLength(MENU_LIST))
@@ -281,7 +281,7 @@ default
         if (index != -1)
         {
             list button_data = llParseStringKeepNulls(llList2String(DATA_LIST, index), ["�"], []);
-            if (llList2String(button_data, 1))
+            if (llList2String(button_data, 1) != "")
             {
                 msg = llList2String(button_data, 1);
             }
@@ -398,7 +398,7 @@ default
             {
                 doit = TRUE;
             }
-            else if (id)
+            else if (id) // OSS::else if (osIsUUID(id) && id != NULL_KEY)
             {
                 if (id == MY_SITTER)
                 {
@@ -608,7 +608,7 @@ default
                 i = -1;
                 while (++i < llGetListLength(MENU_LIST))
                 {
-                    if (llList2Vector(POS_ROT_LIST, i * 2))
+                    if (llList2Vector(POS_ROT_LIST, i * 2) != ZERO_VECTOR)
                     {
                         llSleep(0.2);
                         Readout_Say("{" + llList2String(MENU_LIST, i) + "}" + llList2String(POS_ROT_LIST, i * 2) + llList2String(POS_ROT_LIST, i * 2 + 1));
diff --git a/AVsitter2/prepare-for-oss.py b/AVsitter2/prepare-for-oss.py
new file mode 100644
index 0000000..4944396
--- /dev/null
+++ b/AVsitter2/prepare-for-oss.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+# coding: utf8
+
+import sys, re
+
+def prterr(s):
+    sys.stderr.write(s + "\n")
+
+def main(argc, argv):
+    if argc < 2:
+        prterr(u'Need exactly 1 argument (input filename)')
+        return 1
+
+    # Regex that replaces a line by its OSS version when one's specified.
+    os_re = re.compile(r'^( *)(.*?) // OSS::(.*)$', re.MULTILINE)
+
+    f = open(argv[1], "r");
+    s = f.read()
+    f.close()
+    # The U+FFFD character that AVsitter uses causes problems in OpenSim.
+    # Replace it with U+001F (Unit Separator) which works fine.
+    s = s.replace(b'\xEF\xBF\xBD', b'\x1F')
+
+    s = os_re.sub(r'\1\3', s)
+    sys.stdout.write(s)
+    return 0
+
+ret = main(len(sys.argv), sys.argv)
+if ret is not None and ret > 0:
+    sys.exit(ret)