diff --git a/packages/mlpost/mlpost.0.8.1/opam b/packages/mlpost/mlpost.0.8.1/opam
index 38eaf3a36d1..793b41f0251 100644
--- a/packages/mlpost/mlpost.0.8.1/opam
+++ b/packages/mlpost/mlpost.0.8.1/opam
@@ -38,7 +38,7 @@ patches: ["opam.patch"]
 synopsis: "Interface to Metapost"
 flags: light-uninstall
 url {
-  src: "http://mlpost.lri.fr/download/mlpost-0.8.1.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/mlpost-0.8.1.tar.gz"
   checksum: [
     "sha256=3755c3dbe24445bb2de0d6a5d114725cb0e2ed7ede9c21ee9926ecf1d941862c"
     "md5=a505aa1eb21ac0cdd4732fd10f6ac13a"
diff --git a/packages/mlpost/mlpost.0.8.2/opam b/packages/mlpost/mlpost.0.8.2/opam
index d6eb1fa82c5..e81aced98e5 100644
--- a/packages/mlpost/mlpost.0.8.2/opam
+++ b/packages/mlpost/mlpost.0.8.2/opam
@@ -36,7 +36,7 @@ depends: [
 synopsis: "Interface to Metapost"
 flags: light-uninstall
 url {
-  src: "http://mlpost.lri.fr/download/mlpost-0.8.2.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/mlpost-0.8.2.tar.gz"
   checksum: [
     "sha256=b455afbb28d3adecdeb4ae9fdd34dde57d95a90903bf72e4b88d8ac5e45fcc2a"
     "md5=3d7fbb5d10d65a8362594ca6a3505119"
diff --git a/packages/mysql/mysql.1.0.4/opam b/packages/mysql/mysql.1.0.4/opam
index 9c26f5ebb80..0a1a1b8530e 100644
--- a/packages/mysql/mysql.1.0.4/opam
+++ b/packages/mysql/mysql.1.0.4/opam
@@ -24,7 +24,7 @@ synopsis: "Provides access to mysql databases"
 flags: light-uninstall
 url {
   src:
-    "http://raevnos.pennmush.org/code/ocaml-mysql/ocaml-mysql-1.0.4.tar.gz"
+    "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/ocaml-mysql-1.0.4.tar.gz"
   checksum: [
     "sha256=59d11111558986f0ed237016f9758a3cb99e2fdd0ce0dc128319a3ac2a55259e"
     "md5=76f1282bb7299012669bf40cde78216b"
diff --git a/packages/ocaml-xml-rpc/ocaml-xml-rpc.0.2.3/opam b/packages/ocaml-xml-rpc/ocaml-xml-rpc.0.2.3/opam
index fdb1291bfa5..e5f456eb7b2 100644
--- a/packages/ocaml-xml-rpc/ocaml-xml-rpc.0.2.3/opam
+++ b/packages/ocaml-xml-rpc/ocaml-xml-rpc.0.2.3/opam
@@ -24,7 +24,7 @@ Mellor."""
 flags: light-uninstall
 url {
   src:
-    "http://raevnos.pennmush.org/code/ocaml-xml-rpc/ocaml-xml-rpc-0.2.3.tar.gz"
+    "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/ocaml-xml-rpc-0.2.3.tar.gz"
   checksum: [
     "sha256=3b7a9f8deddd7e57df7cf190dd14f22472005fa310a3d1065615dd784f471f7b"
     "md5=53894f38130a1a02d0507925865e431d"
diff --git a/packages/osdp/osdp.0.5.4/opam b/packages/osdp/osdp.0.5.4/opam
index aaadad92f25..677d5ab99a4 100644
--- a/packages/osdp/osdp.0.5.4/opam
+++ b/packages/osdp/osdp.0.5.4/opam
@@ -25,6 +25,9 @@ numerical optimization solvers. This package will be installed with
 the solver SDPA. It will also be compiled with CSDP and Mosek support
 if they can be found in the PATH."""
 url {
-  src: "https://cavale.enseeiht.fr/osdp/osdp-0.5.4.tgz"
-  checksum: "md5=698641689bd666821fcb78e0834e9a92"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/osdp-0.5.4.tgz"
+  checksum: [
+    "md5=698641689bd666821fcb78e0834e9a92"
+    "sha256=b44fcfb204eff0dc0a229c3b96a6312ad4fafc1d616cdd865894fff170997a17"
+  ]
 }
diff --git a/packages/why/why.2.31/opam b/packages/why/why.2.31/opam
index 8c9bbea0761..664f5bec292 100644
--- a/packages/why/why.2.31/opam
+++ b/packages/why/why.2.31/opam
@@ -51,7 +51,7 @@ to the development of Why3.
 Why is still maintained, in particular to provide the Jessie plug-in
 of Frama-C and the Krakatoa front-end for Java."""
 url {
-  src: "http://why.lri.fr/download/why-2.31.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/why-2.31.tar.gz"
   checksum: [
     "sha256=c2556799f998662792753d1024979576b10521d7cba5929116107f96ec13a480"
     "md5=d647f64049345be5654f8f3fdb077aa4"
diff --git a/packages/why/why.2.32/opam b/packages/why/why.2.32/opam
index ba659534014..5ed1204eeea 100644
--- a/packages/why/why.2.32/opam
+++ b/packages/why/why.2.32/opam
@@ -65,7 +65,7 @@ to the development of Why3.
 Why is still maintained, in particular to provide the Jessie plug-in
 of Frama-C and the Krakatoa front-end for Java."""
 url {
-  src: "http://why.lri.fr/download/why-2.32.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/why-2.32.tar.gz"
   checksum: [
     "sha256=a4365577b852da8d1951eaeb6e2e220645f5cfa270b369d37da2e46b9c1feec4"
     "md5=8983b1058bd651a4eb3db16fa23a458b"
diff --git a/packages/why/why.2.33/opam b/packages/why/why.2.33/opam
index dad99484778..7fc45ccf3ef 100644
--- a/packages/why/why.2.33/opam
+++ b/packages/why/why.2.33/opam
@@ -67,7 +67,7 @@ to the development of Why3.
 Why is still maintained, in particular to provide the Jessie plug-in
 of Frama-C and the Krakatoa front-end for Java."""
 url {
-  src: "http://why.lri.fr/download/why-2.33.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/why-2.33.tar.gz"
   checksum: [
     "sha256=05a2d398b49c447e9897d58596ab9c52bcc4c3877895df590ba77163d1125ece"
     "md5=25ad0493e0cd112f3fe5858aa605344a"
diff --git a/packages/why/why.2.34/opam b/packages/why/why.2.34/opam
index a9488873902..e37825b81ac 100644
--- a/packages/why/why.2.34/opam
+++ b/packages/why/why.2.34/opam
@@ -56,7 +56,7 @@ to the development of Why3.
 Why is still maintained, in particular to provide the Jessie plug-in
 of Frama-C and the Krakatoa front-end for Java."""
 url {
-  src: "http://why.lri.fr/download/why-2.34.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/why-2.34.tar.gz"
   checksum: [
     "sha256=4f861757c13cb7dd4ba8c0c640f04115be147d2d4ca8a55035048e9d305c658c"
     "md5=e622157c9b5cfc4e454a2a98bcc5828c"
diff --git a/packages/why/why.2.35/opam b/packages/why/why.2.35/opam
index fa9fe3a9110..b0bd8ad6791 100644
--- a/packages/why/why.2.35/opam
+++ b/packages/why/why.2.35/opam
@@ -53,7 +53,7 @@ Why is still maintained, in particular to provide the Jessie plug-in
 of Frama-C and the Krakatoa front-end for Java."""
 flags: light-uninstall
 url {
-  src: "http://why.lri.fr/download/why-2.35.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/why-2.35.tar.gz"
   checksum: [
     "sha256=d94359fbfd96d2a251062c1dbfc0ec327e90202a38d897ed5eb54ade636a6af5"
     "md5=10bde72f95de8bc34135a8207cfcc9ec"
diff --git a/packages/why/why.2.36/opam b/packages/why/why.2.36/opam
index 0741fa0ec09..3212015a538 100644
--- a/packages/why/why.2.36/opam
+++ b/packages/why/why.2.36/opam
@@ -50,7 +50,7 @@ of Frama-C and the Krakatoa front-end for Java.
 This version is compatible with Frama-C version Magnesium."""
 flags: light-uninstall
 url {
-  src: "http://why.lri.fr/download/why-2.36.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/why-2.36.tar.gz"
   checksum: [
     "sha256=c3fe2153a1948b14c73e58f6086406a6725ed0ab52e973f2498e3895c4030666"
     "md5=9b26f8d039ab5a04ed16f5ca8b96a780"
diff --git a/packages/why/why.2.37/opam b/packages/why/why.2.37/opam
index 1e77700ea45..d37af03dd2e 100644
--- a/packages/why/why.2.37/opam
+++ b/packages/why/why.2.37/opam
@@ -50,7 +50,7 @@ of Frama-C and the Krakatoa front-end for Java.
 This version is compatible with Frama-C version Aluminium"""
 flags: light-uninstall
 url {
-  src: "http://why.lri.fr/download/why-2.37.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/why-2.37.tar.gz"
   checksum: [
     "sha256=7564a6837278451c93c6ca37cc8d8a2683234130cf06ed180396f26fb042b903"
     "md5=5d1c4e753684413ebb391789efc828fa"
diff --git a/packages/why/why.2.38/opam b/packages/why/why.2.38/opam
index ab31a4c1dec..b31e77ac413 100644
--- a/packages/why/why.2.38/opam
+++ b/packages/why/why.2.38/opam
@@ -51,7 +51,7 @@ of Frama-C and the Krakatoa front-end for Java.
 This version is compatible with Frama-C version Silicon"""
 flags: light-uninstall
 url {
-  src: "http://why.lri.fr/download/why-2.38.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/why-2.38.tar.gz"
   checksum: [
     "sha256=16e174b4190352b229259f2ea47628f9ca4f33053c28c531536f6d350231db12"
     "md5=3add4408954b07a23629b14d74a0a16e"
diff --git a/packages/why/why.2.39/opam b/packages/why/why.2.39/opam
index 0ecb001b802..b48d7e0a338 100644
--- a/packages/why/why.2.39/opam
+++ b/packages/why/why.2.39/opam
@@ -51,7 +51,7 @@ of Frama-C and the Krakatoa front-end for Java.
 This version is compatible with Frama-C version Phosphorus"""
 flags: light-uninstall
 url {
-  src: "http://why.lri.fr/download/why-2.39.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/why-2.39.tar.gz"
   checksum: [
     "sha256=4815111efa3d31c2e209ec98346ac67dd3578fb355adf9d04ff86800a83cc159"
     "md5=d03ea54b2d37039d26a1f2f82b61d860"
diff --git a/packages/why/why.2.40/opam b/packages/why/why.2.40/opam
index 0c70e98a0ef..7a986900859 100644
--- a/packages/why/why.2.40/opam
+++ b/packages/why/why.2.40/opam
@@ -50,7 +50,7 @@ of Frama-C and the Krakatoa front-end for Java.
 This version is compatible with Frama-C version Sulfur"""
 flags: light-uninstall
 url {
-  src: "http://why.lri.fr/download/why-2.40.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/why-2.40.tar.gz"
   checksum: [
     "sha256=285235960f2b4db9a40a5711a1a673611367a4106f6140d71d6ef3a7fb5d3540"
     "md5=8032066e59163e564631ab566a212ce0"
diff --git a/packages/why/why.2.41/opam b/packages/why/why.2.41/opam
index c9345c22f90..58d16e0e58b 100644
--- a/packages/why/why.2.41/opam
+++ b/packages/why/why.2.41/opam
@@ -50,7 +50,7 @@ of Frama-C and the Krakatoa front-end for Java.
 This version is compatible with Frama-C version Chlorine"""
 flags: light-uninstall
 url {
-  src: "http://why.lri.fr/download/why-2.41.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/why-2.41.tar.gz"
   checksum: [
     "sha256=d86596a4c0e897f0f2b8eb3b00bade4feaf3ba31c580a5c605fcc4d77bf37b20"
     "md5=9c5c3eb9f421b8dbbf141b153b051a51"
diff --git a/packages/zenon/zenon.0.8.0/opam b/packages/zenon/zenon.0.8.0/opam
index 6bcc3678a8f..c4b6c6523e0 100644
--- a/packages/zenon/zenon.0.8.0/opam
+++ b/packages/zenon/zenon.0.8.0/opam
@@ -24,7 +24,7 @@ equality), based on the tableau method. Zenon handles first-order
 logic with equality. Its most important feature is that it outputs the
 proofs of the theorems, in Coq-checkable form."""
 url {
-  src: "http://zenon-prover.org/zenon-0.8.0.tar.gz"
+  src: "https://raw.githubusercontent.com/ocaml/opam-source-archives/main/zenon-0.8.0.tar.gz"
   checksum: [
     "sha256=807d946af0295f54edd76ee5ec0563f85a307d7a6b313f98fe6942b32f80ec87"
     "md5=4d82ae5b6dc498a73ef85a353c5da325"