Revert back to 2.28.5

git revert v2.28.5..v2.28.6
git rebase to combine the resulting revert commits

This reverts commit 3a91dad9dceb484eea8b41f8941facafc4520021.
diff --git a/doxygen/input/doc_encdec.h b/doxygen/input/doc_encdec.h
index e29f40f..8c201ed 100644
--- a/doxygen/input/doc_encdec.h
+++ b/doxygen/input/doc_encdec.h
@@ -6,7 +6,19 @@
 /*
  *
  *  Copyright The Mbed TLS Contributors
- *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
  */
 
 /**
diff --git a/doxygen/input/doc_hashing.h b/doxygen/input/doc_hashing.h
index aff7dfa..aaa0c78 100644
--- a/doxygen/input/doc_hashing.h
+++ b/doxygen/input/doc_hashing.h
@@ -6,7 +6,19 @@
 /*
  *
  *  Copyright The Mbed TLS Contributors
- *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
  */
 
 /**
diff --git a/doxygen/input/doc_mainpage.h b/doxygen/input/doc_mainpage.h
index c2343a6..0cad01b 100644
--- a/doxygen/input/doc_mainpage.h
+++ b/doxygen/input/doc_mainpage.h
@@ -6,11 +6,23 @@
 /*
  *
  *  Copyright The Mbed TLS Contributors
- *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
  */
 
 /**
- * @mainpage Mbed TLS v2.28.6 API Documentation
+ * @mainpage Mbed TLS v2.28.5 API Documentation
  *
  * This documentation describes the internal structure of Mbed TLS.  It was
  * automatically generated from specially formatted comment blocks in
diff --git a/doxygen/input/doc_rng.h b/doxygen/input/doc_rng.h
index 5470b75..b298d3b 100644
--- a/doxygen/input/doc_rng.h
+++ b/doxygen/input/doc_rng.h
@@ -6,7 +6,19 @@
 /*
  *
  *  Copyright The Mbed TLS Contributors
- *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
  */
 
 /**
diff --git a/doxygen/input/doc_ssltls.h b/doxygen/input/doc_ssltls.h
index 5757574..6961124 100644
--- a/doxygen/input/doc_ssltls.h
+++ b/doxygen/input/doc_ssltls.h
@@ -6,7 +6,19 @@
 /*
  *
  *  Copyright The Mbed TLS Contributors
- *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
  */
 
 /**
diff --git a/doxygen/input/doc_tcpip.h b/doxygen/input/doc_tcpip.h
index f8d8c69..a705de1 100644
--- a/doxygen/input/doc_tcpip.h
+++ b/doxygen/input/doc_tcpip.h
@@ -6,7 +6,19 @@
 /*
  *
  *  Copyright The Mbed TLS Contributors
- *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
  */
 
 /**
diff --git a/doxygen/input/doc_x509.h b/doxygen/input/doc_x509.h
index 945830f..9049675 100644
--- a/doxygen/input/doc_x509.h
+++ b/doxygen/input/doc_x509.h
@@ -6,7 +6,19 @@
 /*
  *
  *  Copyright The Mbed TLS Contributors
- *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
  */
 
 /**
diff --git a/doxygen/mbedtls.doxyfile b/doxygen/mbedtls.doxyfile
index 1939ac9..f6f160d 100644
--- a/doxygen/mbedtls.doxyfile
+++ b/doxygen/mbedtls.doxyfile
@@ -1,4 +1,4 @@
-PROJECT_NAME           = "Mbed TLS v2.28.6"
+PROJECT_NAME           = "Mbed TLS v2.28.5"
 OUTPUT_DIRECTORY       = ../apidoc/
 FULL_PATH_NAMES        = NO
 OPTIMIZE_OUTPUT_FOR_C  = YES