diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index 74e024d..8a92ff6 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -6830,55 +6830,55 @@
 			echo printf("%1$*2$.*3$f", 1.4142135, 6, 2)
 <			  1.41
 
-							*E1400*
+							*E1500*
 		You cannot mix positional and non-positional arguments: >
 			echo printf("%s%1$s", "One", "Two")
-<			E1400: Cannot mix positional and non-positional
+<			E1500: Cannot mix positional and non-positional
 			arguments: %s%1$s
 
-							*E1401*
+							*E1501*
 		You cannot skip a positional argument in a format string: >
 			echo printf("%3$s%1$s", "One", "Two", "Three")
-<			E1401: format argument 2 unused in $-style
+<			E1501: format argument 2 unused in $-style
 			format: %3$s%1$s
 
-							*E1402*
+							*E1502*
 		You can re-use a [field-width] (or [precision]) argument: >
 			echo printf("%1$d at width %2$d is: %01$*2$d", 1, 2)
 <			1 at width 2 is: 01
 
 		However, you can't use it as a different type: >
 			echo printf("%1$d at width %2$ld is: %01$*2$d", 1, 2)
-<			E1402: Positional argument 2 used as field
+<			E1502: Positional argument 2 used as field
 			width reused as different type: long int/int
 
-							*E1403*
+							*E1503*
 		When a positional argument is used, but not the correct number
 		or arguments is given, an error is raised: >
 			echo printf("%1$d at width %2$d is: %01$*2$.*3$d", 1, 2)
-<			E1403: Positional argument 3 out of bounds:
+<			E1503: Positional argument 3 out of bounds:
 			%1$d at width %2$d is: %01$*2$.*3$d
 
 		Only the first error is reported: >
 			echo printf("%01$*2$.*3$d %4$d", 1, 2)
-<			E1403: Positional argument 3 out of bounds:
+<			E1503: Positional argument 3 out of bounds:
 			%01$*2$.*3$d %4$d
 
-							*E1404*
+							*E1504*
 		A positional argument can be used more than once: >
 			echo printf("%1$s %2$s %1$s", "One", "Two")
 <			One Two One
 
 		However, you can't use a different type the second time: >
 			echo printf("%1$s %2$s %1$d", "One", "Two")
-<			E1404: Positional argument 1 type used
+<			E1504: Positional argument 1 type used
 			inconsistently: int/string
 
-							*E1405*
+							*E1505*
 		Various other errors that lead to a format string being
 		wrongly formatted lead to: >
 			echo printf("%1$d at width %2$d is: %01$*2$.3$d", 1, 2)
-<			E1405: Invalid format specifier:
+<			E1505: Invalid format specifier:
 			%1$d at width %2$d is: %01$*2$.3$d
 
 prompt_getprompt({buf})					*prompt_getprompt()*
diff --git a/runtime/doc/tags b/runtime/doc/tags
index 13baf8f..266b429 100644
--- a/runtime/doc/tags
+++ b/runtime/doc/tags
@@ -4485,12 +4485,6 @@
 E139	message.txt	/*E139*
 E1390	vim9class.txt	/*E1390*
 E140	message.txt	/*E140*
-E1400	builtin.txt	/*E1400*
-E1401	builtin.txt	/*E1401*
-E1402	builtin.txt	/*E1402*
-E1403	builtin.txt	/*E1403*
-E1404	builtin.txt	/*E1404*
-E1405	builtin.txt	/*E1405*
 E141	message.txt	/*E141*
 E142	message.txt	/*E142*
 E143	autocmd.txt	/*E143*
@@ -4502,6 +4496,12 @@
 E149	helphelp.txt	/*E149*
 E15	eval.txt	/*E15*
 E150	helphelp.txt	/*E150*
+E1500	builtin.txt	/*E1500*
+E1501	builtin.txt	/*E1501*
+E1502	builtin.txt	/*E1502*
+E1503	builtin.txt	/*E1503*
+E1504	builtin.txt	/*E1504*
+E1505	builtin.txt	/*E1505*
 E151	helphelp.txt	/*E151*
 E152	helphelp.txt	/*E152*
 E153	helphelp.txt	/*E153*
@@ -6496,6 +6496,7 @@
 confirm()	builtin.txt	/*confirm()*
 connection-refused	message.txt	/*connection-refused*
 console-menus	gui.txt	/*console-menus*
+constructor	vim9class.txt	/*constructor*
 context.vim	ft_context.txt	/*context.vim*
 control	intro.txt	/*control*
 conversion-server	mbyte.txt	/*conversion-server*
@@ -6669,6 +6670,7 @@
 dec-mouse	options.txt	/*dec-mouse*
 decada_members	ft_ada.txt	/*decada_members*
 deepcopy()	builtin.txt	/*deepcopy()*
+default-constructor	vim9class.txt	/*default-constructor*
 defaults.vim	starting.txt	/*defaults.vim*
 defaults.vim-explained	usr_05.txt	/*defaults.vim-explained*
 define-function	userfunc.txt	/*define-function*
@@ -8920,6 +8922,7 @@
 netrw_filehandler	pi_netrw.txt	/*netrw_filehandler*
 netterm-mouse	options.txt	/*netterm-mouse*
 network	pi_netrw.txt	/*network*
+new()	vim9class.txt	/*new()*
 new-5	version5.txt	/*new-5*
 new-6	version6.txt	/*new-6*
 new-7	version7.txt	/*new-7*
@@ -9311,6 +9314,8 @@
 printf-x	builtin.txt	/*printf-x*
 printing	print.txt	/*printing*
 printing-formfeed	print.txt	/*printing-formfeed*
+private-method	vim9class.txt	/*private-method*
+private-variable	vim9class.txt	/*private-variable*
 profile	repeat.txt	/*profile*
 profiling	repeat.txt	/*profiling*
 profiling-variable	eval.txt	/*profiling-variable*
diff --git a/runtime/doc/vim9class.txt b/runtime/doc/vim9class.txt
index 7b9f8b4..5cbdc72 100644
--- a/runtime/doc/vim9class.txt
+++ b/runtime/doc/vim9class.txt
@@ -150,7 +150,7 @@
 A object variable cannot be accessed using the class name.
 
 Private variables ~
-							*E1332* *E1333*
+					*private-variable* *E1332* *E1333*
 On the other hand, if you do not want the object variables to be read directly,
 you can make them private.  This is done by prefixing an underscore to the
 name: >
@@ -182,7 +182,7 @@
 	enddef
 <
 Private methods ~
-							*E1366*
+						*private-method* *E1366*
 If you want object methods to be accessible only from other methods of the
 same class and not used from outside the class, then you can make them
 private.  This is done by prefixing the method name with an underscore: >
@@ -203,7 +203,7 @@
     a._Foo()
 <
 Simplifying the new() method ~
-
+						*new()* *constructor*
 Many constructors take values for the object variables.  Thus you very often
 see this pattern: >
 
@@ -651,7 +651,7 @@
 
 
 Default constructor ~
-
+							*default-constructor*
 In case you define a class without a new() method, one will be automatically
 defined.  This default constructor will have arguments for all the object
 variables, in the order they were specified.  Thus if your class looks like: >
diff --git a/src/errors.h b/src/errors.h
index baf36d5..975e033 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -3532,18 +3532,20 @@
 EXTERN char e_cannot_use_an_object_variable_except_with_the_new_method_str[]
 	INIT(= N_("E1390: Cannot use an object variable \"this.%s\" except with the \"new\" method"));
 #endif
+// E1391 - E1499 unused (reserved for Vim9 class support)
 EXTERN char e_cannot_mix_positional_and_non_positional_str[]
-	INIT(= N_("E1400: Cannot mix positional and non-positional arguments: %s"));
+	INIT(= N_("E1500: Cannot mix positional and non-positional arguments: %s"));
 EXTERN char e_fmt_arg_nr_unused_str[]
-	INIT(= N_("E1401: format argument %d unused in $-style format: %s"));
+	INIT(= N_("E1501: format argument %d unused in $-style format: %s"));
 EXTERN char e_positional_num_field_spec_reused_str_str[]
-	INIT(= N_("E1402: Positional argument %d used as field width reused as different type: %s/%s"));
+	INIT(= N_("E1502: Positional argument %d used as field width reused as different type: %s/%s"));
 EXTERN char e_positional_nr_out_of_bounds_str[]
-	INIT(= N_("E1403: Positional argument %d out of bounds: %s"));
+	INIT(= N_("E1503: Positional argument %d out of bounds: %s"));
 EXTERN char e_positional_arg_num_type_inconsistent_str_str[]
-	INIT(= N_("E1404: Positional argument %d type used inconsistently: %s/%s"));
+	INIT(= N_("E1504: Positional argument %d type used inconsistently: %s/%s"));
 EXTERN char e_invalid_format_specifier_str[]
-	INIT(= N_("E1405: Invalid format specifier: %s"));
+	INIT(= N_("E1505: Invalid format specifier: %s"));
 EXTERN char e_aptypes_is_null_nr_str[]
-	INIT(= "E1408: Internal error: ap_types or ap_types[idx] is NULL: %d: %s");
-// E1391 - E1399 unused
+	INIT(= "E1520: Internal error: ap_types or ap_types[idx] is NULL: %d: %s");
+
+// E1506 - E1519 unused
diff --git a/src/testdir/test_format.vim b/src/testdir/test_format.vim
index f665d15..af364c2 100644
--- a/src/testdir/test_format.vim
+++ b/src/testdir/test_format.vim
@@ -107,65 +107,65 @@
 
   call v9.CheckLegacyAndVim9Failure(["call printf('%1$d%2$d', 1, 3, 4)"], "E767:")
 
-  call v9.CheckLegacyAndVim9Failure(["call printf('%2$d%d', 1, 3)"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%d%2$d', 1, 3)"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%2$*1$d%d', 1, 3)"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%d%2$*1$d', 1, 3)"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%2$.*1$d%d', 1, 3)"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%d%2$.*1$d', 1, 3)"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$%')"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$')"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$_')"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*3$.*d', 3)"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*.*2$d', 3)"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*.*d', 3)"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%*.*1$d', 3)"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%*1$.*d', 3)"], "E1400:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%*1$.*1$d', 3)"], "E1400:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%2$d%d', 1, 3)"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%d%2$d', 1, 3)"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%2$*1$d%d', 1, 3)"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%d%2$*1$d', 1, 3)"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%2$.*1$d%d', 1, 3)"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%d%2$.*1$d', 1, 3)"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$%')"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$')"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$_')"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*3$.*d', 3)"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*.*2$d', 3)"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*.*d', 3)"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%*.*1$d', 3)"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%*1$.*d', 3)"], "E1500:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%*1$.*1$d', 3)"], "E1500:")
 
-  call v9.CheckLegacyAndVim9Failure(["call printf('%2$d', 3, 3)"], "E1401:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%2$d', 3, 3)"], "E1501:")
 
-  call v9.CheckLegacyAndVim9Failure(["call printf('%2$*1$d %1$ld', 3, 3)"], "E1402:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$s %1$*1$d', 3)"], "E1402:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$p %1$*1$d', 3)"], "E1402:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$f %1$*1$d', 3)"], "E1402:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$lud %1$*1$d', 3)"], "E1402:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$llud %1$*1$d', 3)"], "E1402:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$lld %1$*1$d', 3)"], "E1402:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$s %1$*1$d', 3)"], "E1402:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$c %1$*1$d', 3)"], "E1402:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$ld %1$*1$d', 3)"], "E1402:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$ld %2$*1$d', 3, 3)"], "E1402:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*1$ld', 3)"], "E1402:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*1$.*1$ld', 3)"], "E1402:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%2$*1$d %1$ld', 3, 3)"], "E1502:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$s %1$*1$d', 3)"], "E1502:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$p %1$*1$d', 3)"], "E1502:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$f %1$*1$d', 3)"], "E1502:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$lud %1$*1$d', 3)"], "E1502:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$llud %1$*1$d', 3)"], "E1502:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$lld %1$*1$d', 3)"], "E1502:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$s %1$*1$d', 3)"], "E1502:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$c %1$*1$d', 3)"], "E1502:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$ld %1$*1$d', 3)"], "E1502:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$ld %2$*1$d', 3, 3)"], "E1502:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*1$ld', 3)"], "E1502:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*1$.*1$ld', 3)"], "E1502:")
 
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$d%2$d', 3)"], "E1403:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$d%2$d', 3)"], "E1503:")
 
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$d %1$s', 3)"], "E1404:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$ld %1$s', 3)"], "E1404:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$ud %1$d', 3)"], "E1404:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$s %1$f', 3.0)"], "E1404:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*1$d %1$ld', 3)"], "E1404:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$s %1$d', 3)"], "E1404:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$p %1$d', 3)"], "E1404:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$f %1$d', 3)"], "E1404:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$lud %1$d', 3)"], "E1404:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$llud %1$d', 3)"], "E1404:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$lld %1$d', 3)"], "E1404:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$s %1$d', 3)"], "E1404:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$c %1$d', 3)"], "E1404:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$ld %1$d', 3)"], "E1404:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$d %1$s', 3)"], "E1504:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$ld %1$s', 3)"], "E1504:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$ud %1$d', 3)"], "E1504:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$s %1$f', 3.0)"], "E1504:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*1$d %1$ld', 3)"], "E1504:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$s %1$d', 3)"], "E1504:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$p %1$d', 3)"], "E1504:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$f %1$d', 3)"], "E1504:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$lud %1$d', 3)"], "E1504:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$llud %1$d', 3)"], "E1504:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$lld %1$d', 3)"], "E1504:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$s %1$d', 3)"], "E1504:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$c %1$d', 3)"], "E1504:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$ld %1$d', 3)"], "E1504:")
 
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$.2$d', 3)"], "E1405:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%01$d', 3)"], "E1405:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%01$0d', 3)"], "E1405:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*2d', 3)"], "E1405:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*3.*2$d', 3)"], "E1405:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*3$.2$d', 3)"], "E1405:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*3$.*2d', 3)"], "E1405:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$1$.5d', 5)"], "E1405:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$5.1$d', 5)"], "E1405:")
-  call v9.CheckLegacyAndVim9Failure(["call printf('%1$1$.1$d', 5)"], "E1405:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$.2$d', 3)"], "E1505:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%01$d', 3)"], "E1505:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%01$0d', 3)"], "E1505:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*2d', 3)"], "E1505:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*3.*2$d', 3)"], "E1505:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*3$.2$d', 3)"], "E1505:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$*3$.*2d', 3)"], "E1505:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$1$.5d', 5)"], "E1505:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$5.1$d', 5)"], "E1505:")
+  call v9.CheckLegacyAndVim9Failure(["call printf('%1$1$.1$d', 5)"], "E1505:")
 endfunc
 
 func Test_printf_pos_float()
@@ -296,9 +296,9 @@
   call v9.CheckLegacyAndVim9Failure(['echo printf("%1$d", [])'], 'E745:')
   call v9.CheckLegacyAndVim9Failure(['echo printf("%1$d", 1, 2)'], 'E767:')
   call v9.CheckLegacyAndVim9Failure(['echo printf("%*d", 1)'], 'E766:')
-  call v9.CheckLegacyAndVim9Failure(['echo printf("%1$s")'], 'E1403:')
+  call v9.CheckLegacyAndVim9Failure(['echo printf("%1$s")'], 'E1503:')
   call v9.CheckLegacyAndVim9Failure(['echo printf("%1$d", 1.2)'], 'E805:')
-  call v9.CheckLegacyAndVim9Failure(['echo printf("%1$f")'], 'E1403:')
+  call v9.CheckLegacyAndVim9Failure(['echo printf("%1$f")'], 'E1503:')
 endfunc
 
 func Test_printf_pos_64bit()
diff --git a/src/version.c b/src/version.c
index dade6d2..0bb2239 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1950,
+/**/
     1949,
 /**/
     1948,