diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index d2609d0..be749e2 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -52,6 +52,8 @@
   If you never altered io.KeyRepeatRate nor used GetKeyPressedAmount() this won't affect you.
 - Misc: Renamed IMGUI_DISABLE_FORMAT_STRING_FUNCTIONS to IMGUI_DISABLE_DEFAULT_FORMAT_FUNCTIONS. (#1038)
 - Misc: Renamed IMGUI_DISABLE_MATH_FUNCTIONS to IMGUI_DISABLE_DEFAULT_MATH_FUNCTIONS.
+- Fonts: ImFontAtlas::AddCustomRectRegular() now requires an ID larger than 0x110000 (instead of 0x10000) to
+  conform with supporting Unicode planes 1-16 in a future update. ID below 0x110000 will now assert.
 - Backends: DX12: Added extra ID3D12DescriptorHeap parameter to ImGui_ImplDX12_Init() function.
   The value is unused in master branch but will be used by the multi-viewport feature. (#2851) [@obfuscate]
 
diff --git a/imgui.cpp b/imgui.cpp
index 4b58b77..2621a6e 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -353,6 +353,7 @@
  When you are not sure about a old symbol or function name, try using the Search/Find function of your IDE to look for comments or references in all imgui files.
  You can read releases logs https://github.com/ocornut/imgui/releases for more details.
 
+ - 2019/11/21 (1.74) - ImFontAtlas::AddCustomRectRegular() now requires an ID larger than 0x110000 (instead of 0x10000) to conform with supporting Unicode planes 1-16 in a future update. ID below 0x110000 will now assert.
  - 2019/11/19 (1.74) - renamed IMGUI_DISABLE_FORMAT_STRING_FUNCTIONS to IMGUI_DISABLE_DEFAULT_FORMAT_FUNCTIONS for consistency.
  - 2019/11/19 (1.74) - renamed IMGUI_DISABLE_MATH_FUNCTIONS to IMGUI_DISABLE_DEFAULT_MATH_FUNCTIONS for consistency.
  - 2019/10/22 (1.74) - removed redirecting functions/enums that were marked obsolete in 1.52 (October 2017): Begin() (5 arguments signature), IsRootWindowOrAnyChildHovered(), AlignFirstTextHeightToWidgets(), SetNextWindowPosCenter(), ImFont::Glyph. See docs/Changelog.txt or grep this log for details and new names, or see how they were implemented until 1.73.
@@ -1061,7 +1062,7 @@
 // - on Windows you can get those using ToAscii+keyboard state, or via the WM_CHAR message
 void ImGuiIO::AddInputCharacter(unsigned int c)
 {
-    if (c > 0 && c < 0x10000)
+    if (c > 0 && c <= IM_UNICODE_CODEPOINT_MAX)
         InputQueueCharacters.push_back((ImWchar)c);
 }
 
@@ -1071,7 +1072,7 @@
     {
         unsigned int c = 0;
         utf8_chars += ImTextCharFromUtf8(&c, utf8_chars, NULL);
-        if (c > 0 && c < 0x10000)
+        if (c > 0 && c <= IM_UNICODE_CODEPOINT_MAX)
             InputQueueCharacters.push_back((ImWchar)c);
     }
 }
@@ -1463,7 +1464,7 @@
     }
     if ((*str & 0xe0) == 0xc0)
     {
-        *out_char = 0xFFFD; // will be invalid but not end of string
+        *out_char = IM_UNICODE_CODEPOINT_INVALID; // will be invalid but not end of string
         if (in_text_end && in_text_end - (const char*)str < 2) return 1;
         if (*str < 0xc2) return 2;
         c = (unsigned int)((*str++ & 0x1f) << 6);
@@ -1474,7 +1475,7 @@
     }
     if ((*str & 0xf0) == 0xe0)
     {
-        *out_char = 0xFFFD; // will be invalid but not end of string
+        *out_char = IM_UNICODE_CODEPOINT_INVALID; // will be invalid but not end of string
         if (in_text_end && in_text_end - (const char*)str < 3) return 1;
         if (*str == 0xe0 && (str[1] < 0xa0 || str[1] > 0xbf)) return 3;
         if (*str == 0xed && str[1] > 0x9f) return 3; // str[1] < 0x80 is checked below
@@ -1488,7 +1489,7 @@
     }
     if ((*str & 0xf8) == 0xf0)
     {
-        *out_char = 0xFFFD; // will be invalid but not end of string
+        *out_char = IM_UNICODE_CODEPOINT_INVALID; // will be invalid but not end of string
         if (in_text_end && in_text_end - (const char*)str < 4) return 1;
         if (*str > 0xf4) return 4;
         if (*str == 0xf0 && (str[1] < 0x90 || str[1] > 0xbf)) return 4;
@@ -1519,7 +1520,7 @@
         in_text += ImTextCharFromUtf8(&c, in_text, in_text_end);
         if (c == 0)
             break;
-        if (c < 0x10000)    // FIXME: Losing characters that don't fit in 2 bytes
+        if (c <= IM_UNICODE_CODEPOINT_MAX)    // FIXME: Losing characters that don't fit in 2 bytes
             *buf_out++ = (ImWchar)c;
     }
     *buf_out = 0;
@@ -1537,7 +1538,7 @@
         in_text += ImTextCharFromUtf8(&c, in_text, in_text_end);
         if (c == 0)
             break;
-        if (c < 0x10000)
+        if (c <= IM_UNICODE_CODEPOINT_MAX)
             char_count++;
     }
     return char_count;
diff --git a/imgui.h b/imgui.h
index 1d51d93..e2b8f60 100644
--- a/imgui.h
+++ b/imgui.h
@@ -80,6 +80,8 @@
 #else
 #define IM_OFFSETOF(_TYPE,_MEMBER)  ((size_t)&(((_TYPE*)0)->_MEMBER))           // Offset of _MEMBER within _TYPE. Old style macro.
 #endif
+#define IM_UNICODE_CODEPOINT_MAX     0xFFFF                                     // Last Unicode code point supported by this build.
+#define IM_UNICODE_CODEPOINT_INVALID 0xFFFD                                     // Standard invalid Unicode code point.
 
 // Warnings
 #if defined(__clang__)
@@ -2045,7 +2047,7 @@
     ImVector<ImU32> UsedChars;            // Store 1-bit per Unicode code point (0=unused, 1=used)
 
     ImFontGlyphRangesBuilder()          { Clear(); }
-    inline void     Clear()             { int size_in_bytes = 0x10000 / 8; UsedChars.resize(size_in_bytes / (int)sizeof(ImU32)); memset(UsedChars.Data, 0, (size_t)size_in_bytes); }
+    inline void     Clear()             { int size_in_bytes = (IM_UNICODE_CODEPOINT_MAX+1) / 8; UsedChars.resize(size_in_bytes / (int)sizeof(ImU32)); memset(UsedChars.Data, 0, (size_t)size_in_bytes); }
     inline bool     GetBit(int n) const { int off = (n >> 5); ImU32 mask = 1u << (n & 31); return (UsedChars[off] & mask) != 0; }  // Get bit n in the array
     inline void     SetBit(int n)       { int off = (n >> 5); ImU32 mask = 1u << (n & 31); UsedChars[off] |= mask; }               // Set bit n in the array
     inline void     AddChar(ImWchar c)  { SetBit(c); }                          // Add character
@@ -2057,12 +2059,12 @@
 // See ImFontAtlas::AddCustomRectXXX functions.
 struct ImFontAtlasCustomRect
 {
-    unsigned int    ID;             // Input    // User ID. Use <0x10000 to map into a font glyph, >=0x10000 for other/internal/custom texture data.
+    unsigned int    ID;             // Input    // User ID. Use < 0x110000 to map into a font glyph, >= 0x110000 for other/internal/custom texture data.
     unsigned short  Width, Height;  // Input    // Desired rectangle dimension
     unsigned short  X, Y;           // Output   // Packed position in Atlas
-    float           GlyphAdvanceX;  // Input    // For custom font glyphs only (ID<0x10000): glyph xadvance
-    ImVec2          GlyphOffset;    // Input    // For custom font glyphs only (ID<0x10000): glyph display offset
-    ImFont*         Font;           // Input    // For custom font glyphs only (ID<0x10000): target font
+    float           GlyphAdvanceX;  // Input    // For custom font glyphs only (ID < 0x110000): glyph xadvance
+    ImVec2          GlyphOffset;    // Input    // For custom font glyphs only (ID < 0x110000): glyph display offset
+    ImFont*         Font;           // Input    // For custom font glyphs only (ID < 0x110000): target font
     ImFontAtlasCustomRect()         { ID = 0xFFFFFFFF; Width = Height = 0; X = Y = 0xFFFF; GlyphAdvanceX = 0.0f; GlyphOffset = ImVec2(0,0); Font = NULL; }
     bool IsPacked() const           { return X != 0xFFFF; }
 };
@@ -2142,8 +2144,8 @@
     // You can also request your rectangles to be mapped as font glyph (given a font + Unicode point),
     // so you can render e.g. custom colorful icons and use them as regular glyphs.
     // Read misc/fonts/README.txt for more details about using colorful icons.
-    IMGUI_API int               AddCustomRectRegular(unsigned int id, int width, int height);                                                                   // Id needs to be >= 0x10000. Id >= 0x80000000 are reserved for ImGui and ImDrawList
-    IMGUI_API int               AddCustomRectFontGlyph(ImFont* font, ImWchar id, int width, int height, float advance_x, const ImVec2& offset = ImVec2(0,0));   // Id needs to be < 0x10000 to register a rectangle to map into a specific font.
+    IMGUI_API int               AddCustomRectRegular(unsigned int id, int width, int height);                                                                   // Id needs to be >= 0x110000. Id >= 0x80000000 are reserved for ImGui and ImDrawList
+    IMGUI_API int               AddCustomRectFontGlyph(ImFont* font, ImWchar id, int width, int height, float advance_x, const ImVec2& offset = ImVec2(0,0));   // Id needs to be < 0x110000 to register a rectangle to map into a specific font.
     const ImFontAtlasCustomRect*GetCustomRectByIndex(int index) const { if (index < 0) return NULL; return &CustomRects[index]; }
 
     // [Internal]
diff --git a/imgui_demo.cpp b/imgui_demo.cpp
index e19d7fb..1269ace 100644
--- a/imgui_demo.cpp
+++ b/imgui_demo.cpp
@@ -3416,10 +3416,10 @@
                     if (ImGui::TreeNode("Glyphs", "Glyphs (%d)", font->Glyphs.Size))
                     {
                         // Display all glyphs of the fonts in separate pages of 256 characters
-                        for (int base = 0; base < 0x10000; base += 256)
+                        for (unsigned int base = 0; base <= IM_UNICODE_CODEPOINT_MAX; base += 256)
                         {
                             int count = 0;
-                            for (int n = 0; n < 256; n++)
+                            for (unsigned int n = 0; n < 256; n++)
                                 count += font->FindGlyphNoFallback((ImWchar)(base + n)) ? 1 : 0;
                             if (count > 0 && ImGui::TreeNode((void*)(intptr_t)base, "U+%04X..U+%04X (%d %s)", base, base + 255, count, count > 1 ? "glyphs" : "glyph"))
                             {
@@ -3427,7 +3427,7 @@
                                 float cell_spacing = style.ItemSpacing.y;
                                 ImVec2 base_pos = ImGui::GetCursorScreenPos();
                                 ImDrawList* draw_list = ImGui::GetWindowDrawList();
-                                for (int n = 0; n < 256; n++)
+                                for (unsigned int n = 0; n < 256; n++)
                                 {
                                     ImVec2 cell_p1(base_pos.x + (n % 16) * (cell_size + cell_spacing), base_pos.y + (n / 16) * (cell_size + cell_spacing));
                                     ImVec2 cell_p2(cell_p1.x + cell_size, cell_p1.y + cell_size);
diff --git a/imgui_draw.cpp b/imgui_draw.cpp
index f73e0e3..1e4301b 100644
--- a/imgui_draw.cpp
+++ b/imgui_draw.cpp
@@ -1725,7 +1725,8 @@
 
 int ImFontAtlas::AddCustomRectRegular(unsigned int id, int width, int height)
 {
-    IM_ASSERT(id >= 0x10000);
+    // Breaking change on 2019/11/21 (1.74): ImFontAtlas::AddCustomRectRegular() now requires an ID >= 0x110000 (instead of >= 0x10000)
+    IM_ASSERT(id >= 0x110000);
     IM_ASSERT(width > 0 && width <= 0xFFFF);
     IM_ASSERT(height > 0 && height <= 0xFFFF);
     ImFontAtlasCustomRect r;
@@ -1905,7 +1906,7 @@
             dst_tmp.GlyphsSet.Resize(dst_tmp.GlyphsHighest + 1);
 
         for (const ImWchar* src_range = src_tmp.SrcRanges; src_range[0] && src_range[1]; src_range += 2)
-            for (int codepoint = src_range[0]; codepoint <= src_range[1]; codepoint++)
+            for (unsigned int codepoint = src_range[0]; codepoint <= src_range[1]; codepoint++)
             {
                 if (dst_tmp.GlyphsSet.GetBit(codepoint))    // Don't overwrite existing glyphs. We could make this an option for MergeMode (e.g. MergeOverwrite==true)
                     continue;
@@ -2189,7 +2190,7 @@
     for (int i = 0; i < atlas->CustomRects.Size; i++)
     {
         const ImFontAtlasCustomRect& r = atlas->CustomRects[i];
-        if (r.Font == NULL || r.ID > 0x10000)
+        if (r.Font == NULL || r.ID >= 0x110000)
             continue;
 
         IM_ASSERT(r.Font->ContainerAtlas == atlas);
@@ -2453,7 +2454,7 @@
         text += c_len;
         if (c_len == 0)
             break;
-        if (c < 0x10000)
+        if (c <= IM_UNICODE_CODEPOINT_MAX)
             AddChar((ImWchar)c);
     }
 }
@@ -2467,12 +2468,12 @@
 
 void ImFontGlyphRangesBuilder::BuildRanges(ImVector<ImWchar>* out_ranges)
 {
-    int max_codepoint = 0x10000;
-    for (int n = 0; n < max_codepoint; n++)
+    const int max_codepoint = IM_UNICODE_CODEPOINT_MAX;
+    for (int n = 0; n <= max_codepoint; n++)
         if (GetBit(n))
         {
             out_ranges->push_back((ImWchar)n);
-            while (n < max_codepoint - 1 && GetBit(n + 1))
+            while (n < max_codepoint && GetBit(n + 1))
                 n++;
             out_ranges->push_back((ImWchar)n);
         }
@@ -2601,7 +2602,7 @@
 void ImFont::AddRemapChar(ImWchar dst, ImWchar src, bool overwrite_dst)
 {
     IM_ASSERT(IndexLookup.Size > 0);    // Currently this can only be called AFTER the font has been built, aka after calling ImFontAtlas::GetTexDataAs*() function.
-    int index_size = IndexLookup.Size;
+    unsigned int index_size = (unsigned int)IndexLookup.Size;
 
     if (dst < index_size && IndexLookup.Data[dst] == (ImWchar)-1 && !overwrite_dst) // 'dst' already exists
         return;
diff --git a/imgui_widgets.cpp b/imgui_widgets.cpp
index 19f0943..0c5a196 100644
--- a/imgui_widgets.cpp
+++ b/imgui_widgets.cpp
@@ -3157,7 +3157,7 @@
 static int     STB_TEXTEDIT_STRINGLEN(const STB_TEXTEDIT_STRING* obj)                             { return obj->CurLenW; }
 static ImWchar STB_TEXTEDIT_GETCHAR(const STB_TEXTEDIT_STRING* obj, int idx)                      { return obj->TextW[idx]; }
 static float   STB_TEXTEDIT_GETWIDTH(STB_TEXTEDIT_STRING* obj, int line_start_idx, int char_idx)  { ImWchar c = obj->TextW[line_start_idx + char_idx]; if (c == '\n') return STB_TEXTEDIT_GETWIDTH_NEWLINE; ImGuiContext& g = *GImGui; return g.Font->GetCharAdvance(c) * (g.FontSize / g.Font->FontSize); }
-static int     STB_TEXTEDIT_KEYTOTEXT(int key)                                                    { return key >= 0x10000 ? 0 : key; }
+static int     STB_TEXTEDIT_KEYTOTEXT(int key)                                                    { return key >= 0x200000 ? 0 : key; }
 static ImWchar STB_TEXTEDIT_NEWLINE = '\n';
 static void    STB_TEXTEDIT_LAYOUTROW(StbTexteditRow* r, STB_TEXTEDIT_STRING* obj, int line_start_idx)
 {
@@ -3340,6 +3340,10 @@
     if (c >= 0xE000 && c <= 0xF8FF)
         return false;
 
+    // Filter Unicode ranges we are not handling in this build.
+    if (c > IM_UNICODE_CODEPOINT_MAX)
+        return false;
+
     // Generic named filters
     if (flags & (ImGuiInputTextFlags_CharsDecimal | ImGuiInputTextFlags_CharsHexadecimal | ImGuiInputTextFlags_CharsUppercase | ImGuiInputTextFlags_CharsNoBlank | ImGuiInputTextFlags_CharsScientific))
     {
@@ -3763,7 +3767,7 @@
                     s += ImTextCharFromUtf8(&c, s, NULL);
                     if (c == 0)
                         break;
-                    if (c >= 0x10000 || !InputTextFilterCharacter(&c, flags, callback, callback_user_data))
+                    if (!InputTextFilterCharacter(&c, flags, callback, callback_user_data))
                         continue;
                     clipboard_filtered[clipboard_filtered_len++] = (ImWchar)c;
                 }