diff --git a/lama-spec.pdf b/lama-spec.pdf
index 237cb3006..5362cfcb5 100644
Binary files a/lama-spec.pdf and b/lama-spec.pdf differ
diff --git a/runtime/Std.i b/runtime/Std.i
index 1ac1a69ee..ff5588005 100644
--- a/runtime/Std.i
+++ b/runtime/Std.i
@@ -54,3 +54,5 @@ F,kindOf;
 F,compareTags;
 F,flatCompare;
 F,tagHash;
+F,uppercase;
+F,lowercase;
diff --git a/runtime/runtime.c b/runtime/runtime.c
index 6f8c35c1e..ba9224121 100644
--- a/runtime/runtime.c
+++ b/runtime/runtime.c
@@ -566,6 +566,16 @@ static void stringcat (void *p) {
   }
 }
 
+extern int Luppercase (void *v) {
+  ASSERT_UNBOXED("Luppercase:1", v);
+  return BOX(toupper ((int) UNBOX(v)));
+}
+
+extern int Llowercase (void *v) {
+  ASSERT_UNBOXED("Llowercase:1", v);
+  return BOX(tolower ((int) UNBOX(v)));
+}
+
 extern int LmatchSubString (char *subj, char *patt, int pos) {
   data *p = TO_DATA(patt), *s = TO_DATA(subj);
   int   n;
diff --git a/runtime/runtime.h b/runtime/runtime.h
index 16609672c..677429fd7 100644
--- a/runtime/runtime.h
+++ b/runtime/runtime.h
@@ -12,6 +12,7 @@
 # include <regex.h>
 # include <time.h>
 # include <limits.h>
+# include <ctype.h>
 
 # define WORD_SIZE (CHAR_BIT * sizeof(int))
 
diff --git a/spec/08.standard_library.tex b/spec/08.standard_library.tex
index 207a0e207..19d4ada2b 100644
--- a/spec/08.standard_library.tex
+++ b/spec/08.standard_library.tex
@@ -12,6 +12,10 @@ is added implicitly by the compiler and can not be specified by an end user.
 
 The following declarations are accessible:
 
+\descr{\lstinline|fun uppercase (n)|}{Convert \lstinline|n|, treated as ASCII code, into the code of the same symbol in upper case.}
+
+\descr{\lstinline|fun lowercase (n)|}{Convert \lstinline|n|, treated as ASCII code, into the code of the same symbol in lower case.}
+
 \descr{\lstinline|fun assert (n, s, ...)|}{Asserts that \lstinline|n| is non-zero; otherwise raises \lstinline|failure| with
   a corresponding error message.}
 
diff --git a/src/version.ml b/src/version.ml
index 993b5c0f5..da4a1149e 100644
--- a/src/version.ml
+++ b/src/version.ml
@@ -1 +1 @@
-let version = "Version 1.10, 4d56ccc06, Sun Oct 3 17:10:21 2021 +0300"
+let version = "Version 1.10, 594fa7bf8, Sat Oct 30 19:24:25 2021 +0300"