diff --git a/Pipfile b/Pipfile
index 2bbff35..418d2c5 100644
--- a/Pipfile
+++ b/Pipfile
@@ -14,4 +14,4 @@ pytest = "*"
 [dev-packages]
 
 [requires]
-python_version = "3.6"
+python_version = "3.9"
diff --git a/Pipfile.lock b/Pipfile.lock
index 76ead39..a200353 100644
--- a/Pipfile.lock
+++ b/Pipfile.lock
@@ -1,11 +1,11 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "2b691426920d634b995de7a9a62fbac6d9c4ef2a471dc69e9e5b3ffa9407480c"
+            "sha256": "532ea52e572273a9ff1ddfa64ba5bdd00084ca58b174655c01ef5c539dbf3279"
         },
         "pipfile-spec": 6,
         "requires": {
-            "python_version": "3.6"
+            "python_version": "3.9"
         },
         "sources": [
             {
@@ -16,55 +16,79 @@
         ]
     },
     "default": {
-        "atomicwrites": {
+        "asgiref": {
             "hashes": [
-                "sha256:6d1784dea7c0c8d4a5172b6c620f40b6e4cbfdf96d783691f2e1302a7b88e197",
-                "sha256:ae70396ad1a434f9c7046fd2dd196fc04b12f9e91ffb859164193be8b6168a7a"
+                "sha256:92906c611ce6c967347bbfea733f13d6313901d54dcca88195eaeb52b2a8e8ee",
+                "sha256:d1216dfbdfb63826470995d31caed36225dcaf34f182e0fa257a4dd9e86f1b78"
             ],
-            "version": "==1.4.0"
+            "markers": "python_version >= '3.6'",
+            "version": "==3.3.4"
         },
         "attrs": {
             "hashes": [
-                "sha256:08a96c641c3a74e44eb59afb61a24f2cb9f4d7188748e76ba4bb5edfa3cb7d1c",
-                "sha256:f7b7ce16570fe9965acd6d30101a28f62fb4a7f9e926b3bbc9b61f8b04247e72"
+                "sha256:31b2eced602aa8423c2aea9c76a724617ed67cf9513173fd3a4f03e3a929c7e6",
+                "sha256:832aa3cde19744e49938b91fea06d69ecb9e649c93ba974535d08ad92164f700"
             ],
-            "version": "==19.3.0"
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'",
+            "version": "==20.3.0"
         },
         "coverage": {
             "hashes": [
-                "sha256:00f1d23f4336efc3b311ed0d807feb45098fc86dee1ca13b3d6768cdab187c8a",
-                "sha256:01333e1bd22c59713ba8a79f088b3955946e293114479bbfc2e37d522be03355",
-                "sha256:0cb4be7e784dcdc050fc58ef05b71aa8e89b7e6636b99967fadbdba694cf2b65",
-                "sha256:0e61d9803d5851849c24f78227939c701ced6704f337cad0a91e0972c51c1ee7",
-                "sha256:1601e480b9b99697a570cea7ef749e88123c04b92d84cedaa01e117436b4a0a9",
-                "sha256:2742c7515b9eb368718cd091bad1a1b44135cc72468c731302b3d641895b83d1",
-                "sha256:2d27a3f742c98e5c6b461ee6ef7287400a1956c11421eb574d843d9ec1f772f0",
-                "sha256:402e1744733df483b93abbf209283898e9f0d67470707e3c7516d84f48524f55",
-                "sha256:5c542d1e62eece33c306d66fe0a5c4f7f7b3c08fecc46ead86d7916684b36d6c",
-                "sha256:5f2294dbf7875b991c381e3d5af2bcc3494d836affa52b809c91697449d0eda6",
-                "sha256:6402bd2fdedabbdb63a316308142597534ea8e1895f4e7d8bf7476c5e8751fef",
-                "sha256:66460ab1599d3cf894bb6baee8c684788819b71a5dc1e8fa2ecc152e5d752019",
-                "sha256:782caea581a6e9ff75eccda79287daefd1d2631cc09d642b6ee2d6da21fc0a4e",
-                "sha256:79a3cfd6346ce6c13145731d39db47b7a7b859c0272f02cdb89a3bdcbae233a0",
-                "sha256:7a5bdad4edec57b5fb8dae7d3ee58622d626fd3a0be0dfceda162a7035885ecf",
-                "sha256:8fa0cbc7ecad630e5b0f4f35b0f6ad419246b02bc750de7ac66db92667996d24",
-                "sha256:a027ef0492ede1e03a8054e3c37b8def89a1e3c471482e9f046906ba4f2aafd2",
-                "sha256:a3f3654d5734a3ece152636aad89f58afc9213c6520062db3978239db122f03c",
-                "sha256:a82b92b04a23d3c8a581fc049228bafde988abacba397d57ce95fe95e0338ab4",
-                "sha256:acf3763ed01af8410fc36afea23707d4ea58ba7e86a8ee915dfb9ceff9ef69d0",
-                "sha256:adeb4c5b608574a3d647011af36f7586811a2c1197c861aedb548dd2453b41cd",
-                "sha256:b83835506dfc185a319031cf853fa4bb1b3974b1f913f5bb1a0f3d98bdcded04",
-                "sha256:bb28a7245de68bf29f6fb199545d072d1036a1917dca17a1e75bbb919e14ee8e",
-                "sha256:bf9cb9a9fd8891e7efd2d44deb24b86d647394b9705b744ff6f8261e6f29a730",
-                "sha256:c317eaf5ff46a34305b202e73404f55f7389ef834b8dbf4da09b9b9b37f76dd2",
-                "sha256:dbe8c6ae7534b5b024296464f387d57c13caa942f6d8e6e0346f27e509f0f768",
-                "sha256:de807ae933cfb7f0c7d9d981a053772452217df2bf38e7e6267c9cbf9545a796",
-                "sha256:dead2ddede4c7ba6cb3a721870f5141c97dc7d85a079edb4bd8d88c3ad5b20c7",
-                "sha256:dec5202bfe6f672d4511086e125db035a52b00f1648d6407cc8e526912c0353a",
-                "sha256:e1ea316102ea1e1770724db01998d1603ed921c54a86a2efcb03428d5417e489",
-                "sha256:f90bfc4ad18450c80b024036eaf91e4a246ae287701aaa88eaebebf150868052"
-            ],
-            "version": "==5.1"
+                "sha256:004d1880bed2d97151facef49f08e255a20ceb6f9432df75f4eef018fdd5a78c",
+                "sha256:01d84219b5cdbfc8122223b39a954820929497a1cb1422824bb86b07b74594b6",
+                "sha256:040af6c32813fa3eae5305d53f18875bedd079960822ef8ec067a66dd8afcd45",
+                "sha256:06191eb60f8d8a5bc046f3799f8a07a2d7aefb9504b0209aff0b47298333302a",
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+                "sha256:1aa846f56c3d49205c952d8318e76ccc2ae23303351d9270ab220004c580cfe2",
+                "sha256:217658ec7187497e3f3ebd901afdca1af062b42cfe3e0dafea4cced3983739f6",
+                "sha256:24d4a7de75446be83244eabbff746d66b9240ae020ced65d060815fac3423759",
+                "sha256:2910f4d36a6a9b4214bb7038d537f015346f413a975d57ca6b43bf23d6563b53",
+                "sha256:2949cad1c5208b8298d5686d5a85b66aae46d73eec2c3e08c817dd3513e5848a",
+                "sha256:2a3859cb82dcbda1cfd3e6f71c27081d18aa251d20a17d87d26d4cd216fb0af4",
+                "sha256:2cafbbb3af0733db200c9b5f798d18953b1a304d3f86a938367de1567f4b5bff",
+                "sha256:2e0d881ad471768bf6e6c2bf905d183543f10098e3b3640fc029509530091502",
+                "sha256:30c77c1dc9f253283e34c27935fded5015f7d1abe83bc7821680ac444eaf7793",
+                "sha256:3487286bc29a5aa4b93a072e9592f22254291ce96a9fbc5251f566b6b7343cdb",
+                "sha256:372da284cfd642d8e08ef606917846fa2ee350f64994bebfbd3afb0040436905",
+                "sha256:41179b8a845742d1eb60449bdb2992196e211341818565abded11cfa90efb821",
+                "sha256:44d654437b8ddd9eee7d1eaee28b7219bec228520ff809af170488fd2fed3e2b",
+                "sha256:4a7697d8cb0f27399b0e393c0b90f0f1e40c82023ea4d45d22bce7032a5d7b81",
+                "sha256:51cb9476a3987c8967ebab3f0fe144819781fca264f57f89760037a2ea191cb0",
+                "sha256:52596d3d0e8bdf3af43db3e9ba8dcdaac724ba7b5ca3f6358529d56f7a166f8b",
+                "sha256:53194af30d5bad77fcba80e23a1441c71abfb3e01192034f8246e0d8f99528f3",
+                "sha256:5fec2d43a2cc6965edc0bb9e83e1e4b557f76f843a77a2496cbe719583ce8184",
+                "sha256:6c90e11318f0d3c436a42409f2749ee1a115cd8b067d7f14c148f1ce5574d701",
+                "sha256:74d881fc777ebb11c63736622b60cb9e4aee5cace591ce274fb69e582a12a61a",
+                "sha256:7501140f755b725495941b43347ba8a2777407fc7f250d4f5a7d2a1050ba8e82",
+                "sha256:796c9c3c79747146ebd278dbe1e5c5c05dd6b10cc3bcb8389dfdf844f3ead638",
+                "sha256:869a64f53488f40fa5b5b9dcb9e9b2962a66a87dab37790f3fcfb5144b996ef5",
+                "sha256:8963a499849a1fc54b35b1c9f162f4108017b2e6db2c46c1bed93a72262ed083",
+                "sha256:8d0a0725ad7c1a0bcd8d1b437e191107d457e2ec1084b9f190630a4fb1af78e6",
+                "sha256:900fbf7759501bc7807fd6638c947d7a831fc9fdf742dc10f02956ff7220fa90",
+                "sha256:92b017ce34b68a7d67bd6d117e6d443a9bf63a2ecf8567bb3d8c6c7bc5014465",
+                "sha256:970284a88b99673ccb2e4e334cfb38a10aab7cd44f7457564d11898a74b62d0a",
+                "sha256:972c85d205b51e30e59525694670de6a8a89691186012535f9d7dbaa230e42c3",
+                "sha256:9a1ef3b66e38ef8618ce5fdc7bea3d9f45f3624e2a66295eea5e57966c85909e",
+                "sha256:af0e781009aaf59e25c5a678122391cb0f345ac0ec272c7961dc5455e1c40066",
+                "sha256:b6d534e4b2ab35c9f93f46229363e17f63c53ad01330df9f2d6bd1187e5eaacf",
+                "sha256:b7895207b4c843c76a25ab8c1e866261bcfe27bfaa20c192de5190121770672b",
+                "sha256:c0891a6a97b09c1f3e073a890514d5012eb256845c451bd48f7968ef939bf4ae",
+                "sha256:c2723d347ab06e7ddad1a58b2a821218239249a9e4365eaff6649d31180c1669",
+                "sha256:d1f8bf7b90ba55699b3a5e44930e93ff0189aa27186e96071fac7dd0d06a1873",
+                "sha256:d1f9ce122f83b2305592c11d64f181b87153fc2c2bbd3bb4a3dde8303cfb1a6b",
+                "sha256:d314ed732c25d29775e84a960c3c60808b682c08d86602ec2c3008e1202e3bb6",
+                "sha256:d636598c8305e1f90b439dbf4f66437de4a5e3c31fdf47ad29542478c8508bbb",
+                "sha256:deee1077aae10d8fa88cb02c845cfba9b62c55e1183f52f6ae6a2df6a2187160",
+                "sha256:ebe78fe9a0e874362175b02371bdfbee64d8edc42a044253ddf4ee7d3c15212c",
+                "sha256:f030f8873312a16414c0d8e1a1ddff2d3235655a2174e3648b4fa66b3f2f1079",
+                "sha256:f0b278ce10936db1a37e6954e15a3730bea96a0997c26d7fee88e6c396c2086d",
+                "sha256:f11642dddbb0253cc8853254301b51390ba0081750a8ac03f20ea8103f0c56b6"
+            ],
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4' and python_version < '4'",
+            "version": "==5.5"
         },
         "dj-database-url": {
             "hashes": [
@@ -76,96 +100,109 @@
         },
         "django": {
             "hashes": [
-                "sha256:84f370f6acedbe1f3c41e1a02de44ac206efda3355e427139ecb785b5f596d80",
-                "sha256:e8fe3c2b2212dce6126becab7a693157f1a441a07b62ec994c046c76af5bb66d"
+                "sha256:0604e84c4fb698a5e53e5857b5aea945b2f19a18f25f10b8748dbdf935788927",
+                "sha256:21f0f9643722675976004eb683c55d33c05486f94506672df3d6a141546f389d"
             ],
             "index": "pypi",
-            "version": "==2.2.13"
+            "version": "==3.2"
         },
         "django-computed-field": {
             "editable": true,
             "path": "."
         },
-        "importlib-metadata": {
+        "iniconfig": {
             "hashes": [
-                "sha256:0505dd08068cfec00f53a74a0ad927676d7757da81b7436a6eefe4c7cf75c545",
-                "sha256:15ec6c0fd909e893e3a08b3a7c76ecb149122fb14b7efe1199ddd4c7c57ea958"
+                "sha256:011e24c64b7f47f6ebd835bb12a743f2fbe9a26d4cecaa7f53bc4f35ee9da8b3",
+                "sha256:bc3af051d7d14b2ee5ef9969666def0cd1a000e121eaea580d4a313df4b37f32"
             ],
-            "markers": "python_version < '3.8'",
-            "version": "==1.6.1"
+            "version": "==1.1.1"
         },
-        "more-itertools": {
+        "packaging": {
             "hashes": [
-                "sha256:558bb897a2232f5e4f8e2399089e35aecb746e1f9191b6584a151647e89267be",
-                "sha256:7818f596b1e87be009031c7653d01acc46ed422e6656b394b0f765ce66ed4982"
+                "sha256:5b327ac1320dc863dca72f4514ecc086f31186744b84a230374cc1fd776feae5",
+                "sha256:67714da7f7bc052e064859c05c595155bd1ee9f69f76557e21f051443c20947a"
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-            "version": "==8.3.0"
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'",
+            "version": "==20.9"
         },
         "pluggy": {
             "hashes": [
                 "sha256:15b2acde666561e1298d71b523007ed7364de07029219b604cf808bfa1c765b0",
                 "sha256:966c145cd83c96502c3c3868f50408687b38434af77734af1e9ca461a4081d2d"
             ],
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'",
             "version": "==0.13.1"
         },
         "py": {
             "hashes": [
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-                "sha256:c20fdd83a5dbc0af9efd622bee9a5564e278f6380fffcacc43ba6f43db2813b0"
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             ],
-            "version": "==1.8.1"
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'",
+            "version": "==1.10.0"
+        },
+        "pyparsing": {
+            "hashes": [
+                "sha256:c203ec8783bf771a155b207279b9bccb8dea02d8f0c9e5f8ead507bc3246ecc1",
+                "sha256:ef9d7589ef3c200abe66653d3f1ab1033c3c419ae9b9bdb1240a85b024efc88b"
+            ],
+            "markers": "python_version >= '2.6' and python_version not in '3.0, 3.1, 3.2, 3.3'",
+            "version": "==2.4.7"
         },
         "pytest": {
             "hashes": [
-                "sha256:41568ea7ecb4a68d7f63837cf65b92ce8d0105e43196ff2b26622995bb3dc4b2",
-                "sha256:c3c573a29d7c9547fb90217ece8a8843aa0c1328a797e200290dc3d0b4b823be"
+                "sha256:671238a46e4df0f3498d1c3270e5deb9b32d25134c99b7d75370a68cfbe9b634",
+                "sha256:6ad9c7bdf517a808242b998ac20063c41532a570d088d77eec1ee12b0b5574bc"
             ],
             "index": "pypi",
-            "version": "==4.1.1"
+            "version": "==6.2.3"
         },
         "pytest-cov": {
             "hashes": [
-                "sha256:0ab664b25c6aa9716cbf203b17ddb301932383046082c081b9848a0edf5add33",
-                "sha256:230ef817450ab0699c6cc3c9c8f7a829c34674456f2ed8df1fe1d39780f7c87f"
+                "sha256:359952d9d39b9f822d9d29324483e7ba04a3a17dd7d05aa6beb7ea01e359e5f7",
+                "sha256:bdb9fdb0b85a7cc825269a4c56b48ccaa5c7e365054b6038772c32ddcdc969da"
             ],
             "index": "pypi",
-            "version": "==2.6.1"
+            "version": "==2.11.1"
         },
         "pytest-django": {
             "hashes": [
-                "sha256:1a5d33be930e3172fa238643a380414dc369fe8fa4b3c3de25e59ed142950736",
-                "sha256:e88e471d3d0f9acfb6293bb03d0ee8a33ed978734e92ea6b5312163a6c9e87cc"
+                "sha256:10e384e6b8912ded92db64c58be8139d9ae23fb8361e5fc139d8e4f8fc601bc2",
+                "sha256:26f02c16d36fd4c8672390deebe3413678d89f30720c16efb8b2a6bf63b9041f"
             ],
             "index": "pypi",
-            "version": "==3.4.5"
+            "version": "==4.1.0"
         },
-        "pytz": {
+        "pytest-runner": {
             "hashes": [
-                "sha256:a494d53b6d39c3c6e44c3bec237336e14305e4f29bbf800b599253057fbb79ed",
-                "sha256:c35965d010ce31b23eeb663ed3cc8c906275d6be1a34393a1d73a41febf4a048"
+                "sha256:448959d9ada752de2b369cf05c1c0f9e6d2027e7d32441187c16c24c1d4d6e77",
+                "sha256:ca3f58ff4957e8be6c54c55d575b235725cbbcf4dc0d5091c29c6444cfc8a5fe"
             ],
-            "version": "==2020.1"
+            "markers": "python_version >= '3.6'",
+            "version": "==5.3.0"
         },
-        "six": {
+        "pytz": {
             "hashes": [
-                "sha256:30639c035cdb23534cd4aa2dd52c3bf48f06e5f4a941509c8bafd8ce11080259",
-                "sha256:8b74bedcbbbaca38ff6d7491d76f2b06b3592611af620f8426e82dddb04a5ced"
+                "sha256:83a4a90894bf38e243cf052c8b58f381bfe9a7a483f6a9cab140bc7f702ac4da",
+                "sha256:eb10ce3e7736052ed3623d49975ce333bcd712c7bb19a58b9e2089d4057d0798"
             ],
-            "version": "==1.15.0"
+            "version": "==2021.1"
         },
         "sqlparse": {
             "hashes": [
-                "sha256:022fb9c87b524d1f7862b3037e541f68597a730a8843245c349fc93e1643dc4e",
-                "sha256:e162203737712307dfe78860cc56c8da8a852ab2ee33750e33aeadf38d12c548"
+                "sha256:017cde379adbd6a1f15a61873f43e8274179378e95ef3fede90b5aa64d304ed0",
+                "sha256:0f91fd2e829c44362cbcfab3e9ae12e22badaa8a29ad5ff599f9ec109f0454e8"
             ],
-            "version": "==0.3.1"
+            "markers": "python_version >= '3.5'",
+            "version": "==0.4.1"
         },
-        "zipp": {
+        "toml": {
             "hashes": [
-                "sha256:aa36550ff0c0b7ef7fa639055d797116ee891440eac1a56f378e2d3179e0320b",
-                "sha256:c599e4d75c98f6798c509911d08a22e6c021d074469042177c8c86fb92eefd96"
+                "sha256:806143ae5bfb6a3c6e736a764057db0e6a0e05e338b5630894a5f779cabb4f9b",
+                "sha256:b3bda1d108d5dd99f4a20d24d9c348e91c4db7ab1b749200bded2f839ccbe68f"
             ],
-            "version": "==3.1.0"
+            "markers": "python_version >= '2.6' and python_version not in '3.0, 3.1, 3.2, 3.3'",
+            "version": "==0.10.2"
         }
     },
     "develop": {}
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..b0471b7
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,3 @@
+[build-system]
+requires = ["setuptools", "wheel"]
+build-backend = "setuptools.build_meta:__legacy__"
\ No newline at end of file
diff --git a/tox.ini b/tox.ini
index 4d7fab9..d0c7ea1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,7 +3,7 @@ envlist=
   flake8,
   isort,
   bandit,
-  py{36,37}-django{20,21,22,dev}-{base,flake8,prospector},
+  py{36,37,38,39}-django{20,21,22,30,31,32,dev}-{base,flake8,prospector},
   py{27,36,37}-django11-{base,flake8,prospector}
 skip_missing_interpreters=true
 
@@ -12,6 +12,8 @@ python=
   2.7: py27
   3.6: py36
   3.7: py37
+  3.8: py38
+  3.9: py39
 
 [pytest]
 DJANGO_SETTINGS_MODULE = tests.settings
@@ -31,7 +33,10 @@ deps=
   django11: Django>=1.11,<2.0
   django20: Django>=2.0,<2.1
   django21: Django>=2.1.11,<2.2
-  django22: Django>=2.2
+  django22: Django>=2.2,<3.0
+  django30: Django>=3.0,<3.1
+  django31: Django>=3.1,<3.2
+  django32: Django>=3.2
   djangodev: https://github.com/django/django/archive/master.tar.gz
 
 [testenv]
@@ -68,8 +73,7 @@ commands=
 [testenv:prospector]
 deps=
   py27: prospector==0.11.1
-  py36: prospector
-  py37: prospector
+  py3{6,7,8,9}: prospector
   pylint-django
   {[django]deps}
 commands=