diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 719e598..f1f3ac5 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -50,6 +50,8 @@
   Effectively it made io.KeyRepeatRate behave like it was set to (io.KeyRepeatRate + io.KeyRepeatDelay).
   Fixed the code and altered default io.KeyRepeatRate,Delay from 0.250,0.050 to 0.300,0.050 to compensate.
   If you never altered io.KeyRepeatRate nor used GetKeyPressedAmount() this won't affect you.
+- 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 2fdfb94..dcfe6f3 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -351,6 +351,7 @@
  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.
 
+ - 2019/10/29 (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.
  - 2019/10/22 (1.74) - removed redirecting functions/enums that were marked obsolete in 1.52 (October 2017): Begin() (5 arguments signature), IsRootWindowOrAnyChildHovered(), AlignFirstTextHeightToWidgets(), SetNextWindowPosCenter(), ImFont::Glyph. Grep this log for details and new names, or see how they were implemented until 1.73.
  - 2019/10/14 (1.74) - inputs: Fixed a miscalculation in the keyboard/mouse "typematic" repeat delay/rate calculation, used by keys and e.g. repeating mouse buttons as well as the GetKeyPressedAmount() function.
                        if you were using a non-default value for io.KeyRepeatRate (previous default was 0.250), you can add +io.KeyRepeatDelay to it to compensate for the fix.
diff --git a/imgui.h b/imgui.h
index 841506f..7ab1792 100644
--- a/imgui.h
+++ b/imgui.h
@@ -80,6 +80,7 @@
 #else
 #define IM_OFFSETOF(_TYPE,_MEMBER)  ((size_t)&(((_TYPE*)0)->_MEMBER))           // Offset of _MEMBER within _TYPE. Old style macro.
 #endif
+#define IM_UNICODE_MAX_CODEPOINT    (0x10000)
 
 // Warnings
 #if defined(__clang__)
@@ -2042,7 +2043,7 @@
     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_MAX_CODEPOINT / 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
@@ -2054,12 +2055,12 @@
 // 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; }
 };
@@ -2139,8 +2140,8 @@
     // 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 3eedda4..17d2927 100644
--- a/imgui_demo.cpp
+++ b/imgui_demo.cpp
@@ -3401,7 +3401,7 @@
                     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 (int base = 0; base < IM_UNICODE_MAX_CODEPOINT; base += 256)
                         {
                             int count = 0;
                             for (int n = 0; n < 256; n++)
diff --git a/imgui_draw.cpp b/imgui_draw.cpp
index f73e0e3..ad3cf1f 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 2019/10/29 (1.74) - ImFontAtlas::AddCustomRectRegular() now requires an ID larger than 0x110000 (instead of larger than 0x10000)
+    IM_ASSERT(id >= 0x110000);
     IM_ASSERT(width > 0 && width <= 0xFFFF);
     IM_ASSERT(height > 0 && height <= 0xFFFF);
     ImFontAtlasCustomRect r;
@@ -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 >= IM_UNICODE_MAX_CODEPOINT)
             continue;
 
         IM_ASSERT(r.Font->ContainerAtlas == atlas);
@@ -2467,7 +2468,7 @@
 
 void ImFontGlyphRangesBuilder::BuildRanges(ImVector<ImWchar>* out_ranges)
 {
-    int max_codepoint = 0x10000;
+    const int max_codepoint = IM_UNICODE_MAX_CODEPOINT;
     for (int n = 0; n < max_codepoint; n++)
         if (GetBit(n))
         {
diff --git a/imgui_widgets.cpp b/imgui_widgets.cpp
index 1a82f29..ab0f466 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_MAX_CODEPOINT)
+        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;
                 }