diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,23 @@
 
 ## Unreleased
 
+## 0.1.1.1 — 2026-08-29
+
+### Changed
+
+- Every library dependency now carries a PVP upper bound: `aeson`, `containers`,
+  `generic-lens`, `scientific`, `time`, `unordered-containers`. `cabal check`
+  reported these under `missing-upper-bounds`. Without one, a future breaking
+  release of a dependency enters a consumer's build plan unchecked — which is
+  the failure the bound exists to prevent.
+
+  Each bound admits the version this package is built and tested against and
+  stops below the next major.
+
+  `aeson` stops at `<2.3` rather than `<2.4`: baikai-openai 0.5 constrains it to
+  `^>=2.2`, so aeson 2.3 is not reachable for this cohort and a wider bound
+  would assert compatibility that cannot be exercised here.
+
 ## 0.1.1.0 - 2026-07-05
 
 ### Changed
diff --git a/shikumi-trace-otel.cabal b/shikumi-trace-otel.cabal
--- a/shikumi-trace-otel.cabal
+++ b/shikumi-trace-otel.cabal
@@ -1,6 +1,6 @@
 cabal-version:   3.4
 name:            shikumi-trace-otel
-version:         0.1.1.0
+version:         0.1.1.1
 synopsis:
   OpenTelemetry export of shikumi hierarchical trace trees (EP-7)
 
@@ -43,20 +43,20 @@
     Shikumi.Trace.OpenTelemetry
 
   build-depends:
-    , aeson
+    , aeson                                  >=2.2      && <2.3
     , base                                   >=4.20     && <5
-    , containers
-    , generic-lens
+    , containers                             >=0.6      && <0.9
+    , generic-lens                           >=2.2      && <2.4
     , hs-opentelemetry-api                   >=1.0      && <1.1
     , hs-opentelemetry-exporter-otlp         >=1.0      && <1.1
     , hs-opentelemetry-sdk                   >=1.0      && <1.1
     , hs-opentelemetry-semantic-conventions  >=1.40     && <2
     , lens                                   ^>=5.3
-    , scientific
+    , scientific                             >=0.3      && <0.4
     , shikumi-trace                          ^>=0.2.0.0
     , text                                   ^>=2.1
-    , time
-    , unordered-containers
+    , time                                   >=1.12     && <1.17
+    , unordered-containers                   >=0.2      && <0.3
 
 test-suite shikumi-trace-otel-test
   import:         common-options