drop certificate DST Root CA X3

Let's Encrypt planned the transition to ISRG's root certificate ("ISRG Root
X1") on July 8, 2019, but postponed several times.

Finally they found another solution: A certificate 'ISRG Root X1', but
cross-signed with 'DST Root CA X3' and with a livetime that exceeds that
of the root CA. This is said to work for most operating system where root
certificate authorities are just 'trust anchors'.

I doubt this is true for RouterOS, where certificates are just imported
into the certificate store. So let's migrate to 'ISRG Root X1' now.

1 files changed, 4 insertions, 12 deletions

diff --git a/README.md b/README.md
index e102202..c5c0ba5 100644
--- a/README.md
+++ b/README.md
@@ -66,30 +66,22 @@ files to your MikroTik device.
 Then we import the certificates.
 
     [admin@MikroTik] > / certificate import file-name=letsencrypt-R3.pem passphrase=""
-         certificates-imported: 3
+         certificates-imported: 2
          private-keys-imported: 0
                 files-imported: 1
            decryption-failures: 0
       keys-with-no-certificate: 0
 
 For basic verification we rename the certificates and print their count. Make
-sure the certificate count is **three**.
+sure the certificate count is **two**.
 
     [admin@MikroTik] > / certificate set name="R3" [ find where fingerprint="67add1166b020ae61b8f5fc96813c04c2aa589960796865572a3c7e737613dfd" ]
     [admin@MikroTik] > / certificate set name="ISRG-Root-X1" [ find where fingerprint="96bcec06264976f37460779acf28c5a7cfe8a3c0aae11a8ffcee05c0bddf08c6" ]
-    [admin@MikroTik] > / certificate set name="DST-Root-CA-X3" [ find where fingerprint="0687260331a72403d909f105e69bcf0d32e1bd2493ffc6d9206d11bcd6770739" ]
-    [admin@MikroTik] > / certificate print count-only where fingerprint="67add1166b020ae61b8f5fc96813c04c2aa589960796865572a3c7e737613dfd" or fingerprint="96bcec06264976f37460779acf28c5a7cfe8a3c0aae11a8ffcee05c0bddf08c6" or fingerprint="0687260331a72403d909f105e69bcf0d32e1bd2493ffc6d9206d11bcd6770739"
-    3
+    [admin@MikroTik] > / certificate print count-only where fingerprint="67add1166b020ae61b8f5fc96813c04c2aa589960796865572a3c7e737613dfd" or fingerprint="96bcec06264976f37460779acf28c5a7cfe8a3c0aae11a8ffcee05c0bddf08c6"
+    2
 
 Always make sure there are no certificates installed you do not know or want!
 
-Actually we do not require the certificate named `DST Root CA X3`, but as it
-is used by `Let's Encrypt` to cross-sign we install it anyway - this makes
-sure things do not go wrong if the intermediate certificate is replaced.
-The IdenTrust certificate *should* be available from their
-[download page](https://www.identrust.com/support/downloads). The site is
-crap and a good example how to *not* do it.
-
 Now let's download the main scripts and add them in configuration on the fly.
 
     [admin@MikroTik] > :foreach Script in={ "global-config"; "global-config-overlay"; "global-functions" } do={ / system script add name=$Script source=([ / tool fetch check-certificate=yes-without-crl ("https://git.eworm.de/cgit/routeros-scripts/plain/" . $Script) output=user as-value]->"data"); }