diff --git a/.github/codecov.yml b/.github/codecov.yml
new file mode 100644
index 0000000..dda9ad0
--- /dev/null
+++ b/.github/codecov.yml
@@ -0,0 +1,5 @@
+coverage:
+  status:
+    project:
+      default:
+        threshold: 0.5%
\ No newline at end of file
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e31216e..59a9ffc 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,7 +17,7 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.3'
+          - '1.6'
           - '1' # automatically expands to the latest stable 1.x release of Julia.
         os:
           - ubuntu-latest
@@ -44,6 +44,7 @@ jobs:
         env:
           JULIA_NUM_THREADS: 2
       - uses: julia-actions/julia-processcoverage@v1
-      - uses: codecov/codecov-action@v1
+      - uses: codecov/codecov-action@v3
         with:
-          file: lcov.info
+          files: lcov.info
+
diff --git a/Project.toml b/Project.toml
index 85fa7b9..72f6654 100644
--- a/Project.toml
+++ b/Project.toml
@@ -18,7 +18,7 @@ MLJModelInterface = "1.4"
 ScientificTypes = "2.2.2, 3"
 ScientificTypesBase = "2.2.0, 3"
 TextAnalysis = "0.7.3"
-julia = "1.3"
+julia = "1.6"
 
 [extras]
 MLJBase = "a7f614a8-145f-11e9-1d2a-a57a1082229d"
diff --git a/src/bm25_transformer.jl b/src/bm25_transformer.jl
index 0b2013f..e02d3eb 100644
--- a/src/bm25_transformer.jl
+++ b/src/bm25_transformer.jl
@@ -119,7 +119,7 @@ The transformer converts a collection of documents, tokenized or pre-parsed as b
 words/ngrams, to a matrix of [Okapi BM25 document-word
 statistics](https://en.wikipedia.org/wiki/Okapi_BM25). The BM25 scoring function uses both
 term frequency (TF) and inverse document frequency (IDF, defined below), as in
-[`TfidfTransformer`](ref), but additionally adjusts for the probability that a user will
+[`TfidfTransformer`](@ref), but additionally adjusts for the probability that a user will
 consider a search result relevant based, on the terms in the search query and those in
 each document.