diff --git a/CHANGELOG.md b/CHANGELOG.md
index b329859..b7230ca 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
-# 1.13.4 (Unreleased)
+# 1.14.0 (Unreleased)
 
+This release updates the supported version of Unicode from Unicode 13 to Unicode 15. This is a backwards-compatible change that means that cty supports normalization and segmentation of strings containing new Unicode characters. The algorithms for normalization and segmentation themselves are unchanged.
+
+* `cty`: The `cty.String` type will now normalize incoming string values using the Unicode 15 normalization rules.
+* `function/stdlib`: The various string functions which split strings into individual characters as part of their work will now use the Unicode 15 version of the text segmentation algorithm to do so.
 
 # 1.13.3 (August 24, 2023)
 
diff --git a/cty/ctystrings/prefix.go b/cty/ctystrings/prefix.go
index ac62e18..bbf0452 100644
--- a/cty/ctystrings/prefix.go
+++ b/cty/ctystrings/prefix.go
@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"unicode/utf8"
 
-	"github.com/apparentlymart/go-textseg/v13/textseg"
+	"github.com/apparentlymart/go-textseg/v15/textseg"
 	"golang.org/x/text/unicode/norm"
 )
 
diff --git a/cty/function/stdlib/format.go b/cty/function/stdlib/format.go
index d04a5ee..2339cc3 100644
--- a/cty/function/stdlib/format.go
+++ b/cty/function/stdlib/format.go
@@ -6,7 +6,7 @@ import (
 	"math/big"
 	"strings"
 
-	"github.com/apparentlymart/go-textseg/v13/textseg"
+	"github.com/apparentlymart/go-textseg/v15/textseg"
 
 	"github.com/zclconf/go-cty/cty"
 	"github.com/zclconf/go-cty/cty/convert"
diff --git a/cty/function/stdlib/string.go b/cty/function/stdlib/string.go
index 57ebce1..f79bf98 100644
--- a/cty/function/stdlib/string.go
+++ b/cty/function/stdlib/string.go
@@ -6,7 +6,7 @@ import (
 	"sort"
 	"strings"
 
-	"github.com/apparentlymart/go-textseg/v13/textseg"
+	"github.com/apparentlymart/go-textseg/v15/textseg"
 
 	"github.com/zclconf/go-cty/cty"
 	"github.com/zclconf/go-cty/cty/function"
diff --git a/go.mod b/go.mod
index f07ab8c..a9b678e 100644
--- a/go.mod
+++ b/go.mod
@@ -1,10 +1,10 @@
 module github.com/zclconf/go-cty
 
 require (
-	github.com/apparentlymart/go-textseg/v13 v13.0.0
+	github.com/apparentlymart/go-textseg/v15 v15.0.0
 	github.com/google/go-cmp v0.3.1
 	github.com/vmihailenco/msgpack/v5 v5.3.5
-	golang.org/x/text v0.3.8
+	golang.org/x/text v0.11.0
 )
 
 require (
diff --git a/go.sum b/go.sum
index cb4f7b0..a2a7960 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,5 @@
-github.com/apparentlymart/go-textseg/v13 v13.0.0 h1:Y+KvPE1NYz0xl601PVImeQfFyEy6iT90AvPUL1NNfNw=
-github.com/apparentlymart/go-textseg/v13 v13.0.0/go.mod h1:ZK2fH7c4NqDTLtiYLvIkEghdlcqw7yxLeM89kiTRPUo=
+github.com/apparentlymart/go-textseg/v15 v15.0.0 h1:uYvfpb3DyLSCGWnctWKGj857c6ew1u1fNQOlOtuGxQY=
+github.com/apparentlymart/go-textseg/v15 v15.0.0/go.mod h1:K8XmNZdhEBkdlyDdvbmmsvpAG721bKi0joRfFdHIWJ4=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -14,8 +14,8 @@ github.com/vmihailenco/msgpack/v5 v5.3.5 h1:5gO0H1iULLWGhs2H5tbAHIZTV8/cYafcFOr9
 github.com/vmihailenco/msgpack/v5 v5.3.5/go.mod h1:7xyJ9e+0+9SaZT0Wt1RGleJXzli6Q/V5KbhBonMG9jc=
 github.com/vmihailenco/tagparser/v2 v2.0.0 h1:y09buUbR+b5aycVFQs/g70pqKVZNBmxwAhO7/IwNM9g=
 github.com/vmihailenco/tagparser/v2 v2.0.0/go.mod h1:Wri+At7QHww0WTrCBeu4J6bNtoV6mEfg5OIWRZA9qds=
-golang.org/x/text v0.3.8 h1:nAL+RVCQ9uMn3vJZbV+MRnydTJFPf8qqY42YiA6MrqY=
-golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=
+golang.org/x/text v0.11.0 h1:LAntKIrcmeSKERyiOh0XMV39LXS8IE9UL2yP7+f5ij4=
+golang.org/x/text v0.11.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=