diff --git a/.github/workflows/Linux_options.yml b/.github/workflows/Linux_options.yml
index 7d1f1cb6..62ccf346 100644
--- a/.github/workflows/Linux_options.yml
+++ b/.github/workflows/Linux_options.yml
@@ -74,22 +74,6 @@ jobs:
         make
         make install
 
-    - name: checkout-sp
-      uses: actions/checkout@v2
-      with:
-        repository: NOAA-EMC/NCEPLIBS-sp
-        path: sp
-        ref: v2.3.3
-
-    - name: build-sp
-      run: |
-        cd sp
-        mkdir build
-        cd build
-        cmake -DCMAKE_INSTALL_PREFIX=~/sp -DBUILD_8=ON ..
-        make -j2
-        make install
-
     - name: cache-ip
       id: cache-ip
       uses: actions/cache@v3
@@ -114,22 +98,6 @@ jobs:
         cmake .. -DCMAKE_INSTALL_PREFIX=~/ip -DCMAKE_PREFIX_PATH=~/sp
         make -j2
         make install
-          
-    - name: checkout-ip2
-      uses: actions/checkout@v2
-      with:
-        repository: NOAA-EMC/NCEPLIBS-ip2
-        path: ip2
-        ref: develop
-
-    - name: build-ip2
-      run: |
-        cd ip2
-        mkdir build
-        cd build
-        cmake .. -DCMAKE_INSTALL_PREFIX=~/ip2 -DCMAKE_PREFIX_PATH=~
-        make -j2
-        make install        
 
     - name: checkout
       uses: actions/checkout@v2
@@ -141,6 +109,6 @@ jobs:
         cd wgrib2
         mkdir b
         cd b
-        cmake ${{ matrix.config.options }} -DCMAKE_PREFIX_PATH="~/sp;~/ip;~/ip2" ..
+        cmake ${{ matrix.config.options }} -DCMAKE_PREFIX_PATH="~/ip" ..
         make VERBOSE=1
         ctest --verbose --output-on-failure --rerun-failed
diff --git a/.github/workflows/Spack.yml b/.github/workflows/Spack.yml
index cb1d9283..faede806 100644
--- a/.github/workflows/Spack.yml
+++ b/.github/workflows/Spack.yml
@@ -19,7 +19,7 @@ jobs:
     strategy:
       matrix:
         os: ["ubuntu-latest"]
-        variants: ["ipolates=0", "ipolates=1"]
+        variants: ["~ipolates", "+ipolates"]
 
     runs-on: ${{ matrix.os }}
 
diff --git a/.github/workflows/developer.yml b/.github/workflows/developer.yml
index f8734021..9f4defff 100644
--- a/.github/workflows/developer.yml
+++ b/.github/workflows/developer.yml
@@ -57,54 +57,6 @@ jobs:
         make
         make install
 
-    - name: checkout-sp
-      uses: actions/checkout@v4
-      with:
-        repository: NOAA-EMC/NCEPLIBS-sp
-        path: sp
-        ref: develop
-
-    - name: build-sp
-      run: |
-        cd sp
-        mkdir build
-        cd build
-        cmake -DCMAKE_INSTALL_PREFIX=~/sp -DBUILD_8=ON ..
-        make -j2
-        make install
-
-    - name: checkout-ip
-      uses: actions/checkout@v4
-      with:
-        repository: NOAA-EMC/NCEPLIBS-ip
-        path: ip
-        ref: v3.3.3
-  
-    - name: build-ip
-      run: |
-        cd ip
-        mkdir build
-        cd build
-        cmake .. -DCMAKE_INSTALL_PREFIX=~/ip -DCMAKE_PREFIX_PATH=~/sp
-        make -j2
-        make install
-
-    - name: checkout-ip2
-      uses: actions/checkout@v4
-      with:
-        repository: NOAA-EMC/NCEPLIBS-ip2
-        path: ip2
-        ref: develop
-
-    - name: build-ip2
-      run: |
-        cd ip2
-        mkdir build
-        cd build
-        cmake .. -DCMAKE_INSTALL_PREFIX=~/ip2 -DCMAKE_PREFIX_PATH=~
-        make -j2
-        make install        
-
     - name: checkout-ip
       uses: actions/checkout@v4
       with:
@@ -141,7 +93,7 @@ jobs:
         export CFLAGS='-Wall -g -fprofile-abs-path -fprofile-arcs -ftest-coverage -O0'        
         export FCFLAGS='-Wall -g -fprofile-abs-path -fprofile-arcs -ftest-coverage -O0'        
         export FFLAGS='-Wall -g -fprofile-abs-path -fprofile-arcs -ftest-coverage -O0'        
-        cmake .. -DENABLE_DOCS=ON -DFTP_TEST_FILES=ON -DCMAKE_PREFIX_PATH="~/ip;~/ip2;~/sp;~/jasper" -DTEST_FILE_DIR=/home/runner/data -DUSE_NETCDF4=ON -DUSE_AEC=ON -DUSE_IPOLATES=ON -DUSE_JASPER=ON
+        cmake .. -DENABLE_DOCS=ON -DFTP_TEST_FILES=ON -DCMAKE_PREFIX_PATH="~/ip;~/jasper" -DTEST_FILE_DIR=/home/runner/data -DUSE_NETCDF4=ON -DUSE_AEC=ON -DUSE_IPOLATES=ON -DUSE_JASPER=ON
         make VERBOSE=1
         ctest --verbose --output-on-failure --rerun-failed
         gcovr --root .. -v  --html-details --exclude ../tests --exclude CMakeFiles --print-summary -o test-coverage.html &> /dev/null
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3edc0988..4d096f0e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -93,7 +93,7 @@ endif()
 # If user wants to use NCEPLIBS-ip, find it and the sp library.
 message(STATUS "Checking if the user want to use NCEPLIBS-ip...")
 if(USE_IPOLATES)
-  find_package(ip CONFIG REQUIRED)
+  find_package(ip 5.1.0 CONFIG REQUIRED)
   list(APPEND definitions_list -DIPOLATES_LIB="ipolates_lib_d")
   list(APPEND definitions_list -DUSE_IPOLATES)
 endif()
diff --git a/spack/package.py b/spack/package.py
index b86a3319..b1662479 100644
--- a/spack/package.py
+++ b/spack/package.py
@@ -86,9 +86,9 @@ def url_for_version(self, version):
     )
     variant(
         "ipolates",
-        default="3",
-        description="Use to interpolate to new grids (0 = OFF, 1 = ip, 3 = ip2)",
-        values=("0", "1", "3"),
+        default=False,
+        description="Use to interpolate to new grids",
+        when="@3.3:",
     )
     variant(
         "spectral", default=False, description="Spectral interpolation in -new_grid", when="@:3.1"
@@ -151,9 +151,7 @@ def url_for_version(self, version):
     conflicts("+openmp", when="%apple-clang")
 
     depends_on("wget", type=("build"), when="@:3.1 +netcdf4")
-    depends_on("ip@:3", when="@3.2 ipolates=1")
-    depends_on("ip2", when="@3.2 ipolates=3")
-    depends_on("ip@4.1:", when="@develop ipolates=1")
+    depends_on("ip@5.1:", when="@develop +ipolates")
     depends_on("libaec@1.0.6:", when="@3.2: +aec")
     depends_on("netcdf-c", when="@3.2: +netcdf4")
     depends_on("jasper@:2", when="@3.2: +jasper")