diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index cd0b2cf..c4b9f9c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,7 +15,7 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.6' # Replace this with the minimum Julia version that your package supports. E.g. if your package requires Julia 1.5 or higher, change this to '1.5'.
+          - '1.9' # Replace this with the minimum Julia version that your package supports. E.g. if your package requires Julia 1.5 or higher, change this to '1.5'.
           - '1' # Leave this line unchanged. '1' will automatically expand to the latest stable 1.x release of Julia.
         os:
           - ubuntu-latest
@@ -27,7 +27,7 @@ jobs:
         with:
           version: ${{ matrix.version }}
           arch: ${{ matrix.arch }}
-      - uses: actions/cache@v1
+      - uses: actions/cache@v4
         env:
           cache-name: cache-artifacts
         with:
diff --git a/Project.toml b/Project.toml
index 6ff8d04..dd48fbd 100644
--- a/Project.toml
+++ b/Project.toml
@@ -34,7 +34,7 @@ StatsModels = "0.7"
 StatsFuns = "0.9, 1"
 Tables = "1"
 Vcov = "0.8"
-julia = "1.6"
+julia = "1.9"
 
 [extras]
 CSV = "336ed68f-0bac-5ca0-87d4-7b16caf5d00b"
diff --git a/src/fit.jl b/src/fit.jl
index a504ad2..5570936 100644
--- a/src/fit.jl
+++ b/src/fit.jl
@@ -67,12 +67,12 @@ function regife(
            Symbol(fesymbol(a)) ∉ factor_vars && error("FixedEffect should correspond to id or time dimension of the factor model")
        end
     end
-    fes, ids, fekeys, formula = FixedEffectModels.parse_fixedeffect(df, formula)
+    fes, ids, fekeys, formula = parse_fixedeffect(df, formula)
     has_fes = !isempty(fes)
     has_fes_intercept = false
     ## Compute factors, an array of AbtractFixedEffects
     if has_fes
-        if any([isa(fe.interaction, Ones) for fe in fes])
+        if any([isa(fe.interaction, UnitWeights) for fe in fes])
                 formula = FormulaTerm(formula.lhs, tuple(ConstantTerm(0), (t for t in eachterm(formula.rhs) if t!= ConstantTerm(1))...))
                 has_fes_intercept = true
         end
@@ -93,7 +93,7 @@ function regife(
 
     ##############################################################################
     ##
-    ## Construict vector y and matrix X
+    ## Construct vector y and matrix X
     ##
     ##############################################################################
     subdf = Tables.columntable((; (x => disallowmissing(view(df[!, x], esample)) for x in unique(vcat(vars)))...))
diff --git a/src/utils/formula.jl b/src/utils/formula.jl
index bf6f042..e242206 100644
--- a/src/utils/formula.jl
+++ b/src/utils/formula.jl
@@ -14,3 +14,13 @@ eachterm(@nospecialize(x::NTuple{N, AbstractTerm})) where {N} = x
 ##############################################################################
 fesymbol(t::FixedEffectModels.FixedEffectTerm) = t.x
 fesymbol(t::FunctionTerm{typeof(fe)}) = Symbol(t.args[1])
+
+function parse_fixedeffect(df, formula)
+    if isdefined(FixedEffectModels, :parse_fe)
+        formula, formula_fes = FixedEffectModels.parse_fe(formula)
+        fes, ids, fekeys = FixedEffectModels.parse_fixedeffect(df, formula_fes)
+    else
+        fes, ids, fekeys, formula = FixedEffectModels.parse_fixedeffect(df, formula)
+    end
+    return fes, ids, fekeys, formula
+end
\ No newline at end of file