I've been getting the following error for the past few days even though this morning Discovery updated around 219 packages:
sudo apt-get update
[sudo] password for nigel:
Get:1 http://archive.neon.kde.org/user bionic InRelease [153 kB]
Get:2 http://il.archive.ubuntu.com/ubuntu bionic InRelease [242 kB]
Get:4 http://il.archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Get:5 http://il.archive.ubuntu.com/ubuntu bionic-backports InRelease [74.6 kB]
Get:3 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]
Ign:6 http://il.archive.ubuntu.com/ubuntu bionic/main i386 Packages
Ign:7 http://il.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
Ign:6 http://il.archive.ubuntu.com/ubuntu bionic/main i386 Packages
Ign:7 http://il.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
Get:6 http://il.archive.ubuntu.com/ubuntu bionic/main i386 Packages [337 kB]
Err:6 http://il.archive.ubuntu.com/ubuntu bionic/main i386 Packages
File has unexpected size (1328087 != 336742). Mirror sync in progress? [IP: 192.115.211.70 80]
Hashes of expected file:
- Filesize:336742 [weak]
- SHA512:886c571e57fa1b831d0a536023bcd48ab1be748c3fe3791f42308c7d4dd6610af3d8caffcaf23c7ce6dd5fcbdf5497e8a309548c6d2ea0db752b008cfaa329ee
- SHA256:db5d7d2e0ec397803d97e3393848ac49462535027bb13b828695dd24a2c22df7
- SHA1:c79d5492edafe85c6b8e5f6c7e4a562d680b3bcf [weak]
- MD5Sum:fca999f8d16c89380d7682111cc9b41c [weak]
Release file created at: Wed, 20 Mar 2019 14:20:14 +0000
Get:7 http://il.archive.ubuntu.com/ubuntu bionic/main amd64 Packages [2,228 kB]
Err:7 http://il.archive.ubuntu.com/ubuntu bionic/main amd64 Packages

Reading package lists... Done
E: Repository 'http://il.archive.ubuntu.com/ubuntu bionic-updates InRelease' changed its 'Origin' value from 'user bionic' to 'Ubuntu'
E: Repository 'http://il.archive.ubuntu.com/ubuntu bionic-updates InRelease' changed its 'Label' value from 'KDE neon - User Edition' to 'Ubuntu'
N: Repository 'http://il.archive.ubuntu.com/ubuntu bionic-updates InRelease' changed its 'Version' value from '' to '18.04'
E: Repository 'http://il.archive.ubuntu.com/ubuntu bionic-updates InRelease' changed its 'Suite' value from 'bionic' to 'bionic-updates'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
E: Repository 'http://security.ubuntu.com/ubuntu bionic-security InRelease' changed its 'Origin' value from 'user bionic' to 'Ubuntu'
E: Repository 'http://security.ubuntu.com/ubuntu bionic-security InRelease' changed its 'Label' value from 'KDE neon - User Edition' to 'Ubuntu'
N: Repository 'http://security.ubuntu.com/ubuntu bionic-security InRelease' changed its 'Version' value from '' to '18.04'
E: Repository 'http://security.ubuntu.com/ubuntu bionic-security InRelease' changed its 'Suite' value from 'bionic' to 'bionic-security'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.

Why can Discovery update packages but apt-get can't -- and how can I fix it?
Thank you,
Nigel

My understanding is that apt-get is somewhat deprecated with apt now being that default console command.

Using apt it is also recommended that the subsequent command should be apt full-upgrade rather than dist-upgrade. Did have one time when full-upgrade threw up errors so I dist-upgrade - all ok - then full-grade which ran without problems. No idea why but it worked.

Thus I always sudo apt update then sudo apt full-upgrade (then apt autoremove just in case).

May be worth a try

Thanks for that; it seemed to help. Here is my output:
sudo apt update
[sudo] password for nigel:
Get:1 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]
E: Repository 'http://security.ubuntu.com/ubuntu bionic-security InRelease' changed its 'Origin' value from 'user bionic' to 'Ubuntu'
E: Repository 'http://security.ubuntu.com/ubuntu bionic-security InRelease' changed its 'Label' value from 'KDE neon - User Edition' to 'Ubuntu'
N: Repository 'http://security.ubuntu.com/ubuntu bionic-security InRelease' changed its 'Version' value from '' to '18.04'
E: Repository 'http://security.ubuntu.com/ubuntu bionic-security InRelease' changed its 'Suite' value from 'bionic' to 'bionic-security'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
Do you want to accept these changes and continue updating from this repository? [y/N] y
Get:2 http://il.archive.ubuntu.com/ubuntu bionic InRelease [242 kB]
Get:3 http://il.archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Get:4 http://il.archive.ubuntu.com/ubuntu bionic-backports InRelease [74.6 kB]
Get:5 http://archive.neon.kde.org/user bionic InRelease [153 kB]
Ign:6 http://il.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
Ign:7 http://il.archive.ubuntu.com/ubuntu bionic/main i386 Packages
Ign:6 http://il.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
Ign:7 http://il.archive.ubuntu.com/ubuntu bionic/main i386 Packages
E: Repository 'http://il.archive.ubuntu.com/ubuntu bionic-updates InRelease' changed its 'Origin' value from 'user bionic' to 'Ubuntu'
E: Repository 'http://il.archive.ubuntu.com/ubuntu bionic-updates InRelease' changed its 'Label' value from 'KDE neon - User Edition' to 'Ubuntu'
N: Repository 'http://il.archive.ubuntu.com/ubuntu bionic-updates InRelease' changed its 'Version' value from '' to '18.04'
E: Repository 'http://il.archive.ubuntu.com/ubuntu bionic-updates InRelease' changed its 'Suite' value from 'bionic' to 'bionic-updates'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
Do you want to accept these changes and continue updating from this repository? [y/N] y
Get:6 http://il.archive.ubuntu.com/ubuntu bionic/main amd64 Packages [2,228 kB]
Err:6 http://il.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
File has unexpected size (1343916 != 2228413). Mirror sync in progress? [IP: 192.115.211.70 80]
Hashes of expected file:
- Filesize:2228413 [weak]
- SHA512:40d24577e8e862ff30bd9d1f68df3be763258ce6a690f8daf5cb0aa12c363c14876813776f188a1a783ab2191b5e4f27ecfd454f20f2824c21e82f4e1facf0f1
- SHA256:b97a2c6067ebe3a2feb20940faa40a4598a18db722676cdbe3a7aa726165f14e
- SHA1:781a95f61fd759ebe2f2f3891e8057163d014c4d [weak]
- MD5Sum:feeebc70f5724b1bc2f242f75e9e02ca [weak]
Release file created at: Wed, 20 Mar 2019 14:20:14 +0000
Get:8 http://security.ubuntu.com/ubuntu bionic-security/main i386 Packages [287 kB]
Get:7 http://il.archive.ubuntu.com/ubuntu bionic/main i386 Packages [337 kB]
Err:7 http://il.archive.ubuntu.com/ubuntu bionic/main i386 Packages

Get:9 http://security.ubuntu.com/ubuntu bionic-security/main amd64 Packages [380 kB]
Get:10 http://il.archive.ubuntu.com/ubuntu bionic-updates/main i386 Packages [530 kB]
Get:11 http://il.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages [638 kB]
Get:12 http://security.ubuntu.com/ubuntu bionic-security/main amd64 DEP-11 Metadata [14.9 kB]
Get:13 http://il.archive.ubuntu.com/ubuntu bionic-updates/main amd64 DEP-11 Metadata [276 kB]
Get:14 http://security.ubuntu.com/ubuntu bionic-security/restricted i386 Packages [4,280 B]
Get:15 http://security.ubuntu.com/ubuntu bionic-security/restricted amd64 Packages [4,296 B]
Get:16 http://il.archive.ubuntu.com/ubuntu bionic-updates/restricted i386 Packages [6,960 B]
Get:17 http://il.archive.ubuntu.com/ubuntu bionic-updates/restricted amd64 Packages [6,996 B]
Get:18 http://il.archive.ubuntu.com/ubuntu bionic-updates/universe amd64 Packages [948 kB]
Get:19 http://security.ubuntu.com/ubuntu bionic-security/universe i386 Packages [252 kB]
Get:20 http://il.archive.ubuntu.com/ubuntu bionic-updates/universe i386 Packages [935 kB]
Get:21 http://security.ubuntu.com/ubuntu bionic-security/universe amd64 Packages [257 kB]
Get:22 http://il.archive.ubuntu.com/ubuntu bionic-updates/universe amd64 DEP-11 Metadata [227 kB]
Get:23 http://il.archive.ubuntu.com/ubuntu bionic-updates/multiverse amd64 Packages [6,644 B]
Get:24 http://il.archive.ubuntu.com/ubuntu bionic-updates/multiverse i386 Packages [6,788 B]
Get:25 http://il.archive.ubuntu.com/ubuntu bionic-updates/multiverse amd64 DEP-11 Metadata [2,468 B]
Get:26 http://security.ubuntu.com/ubuntu bionic-security/universe amd64 DEP-11 Metadata [35.8 kB]
Get:27 http://security.ubuntu.com/ubuntu bionic-security/multiverse i386 Packages [4,152 B]
Get:28 http://security.ubuntu.com/ubuntu bionic-security/multiverse amd64 Packages [4,004 B]
Get:29 http://security.ubuntu.com/ubuntu bionic-security/multiverse amd64 DEP-11 Metadata [2,464 B]
Fetched 5,475 kB in 22s (253 kB/s)
Reading package lists... Done
E: Failed to fetch http://il.archive.ubuntu.com/ubuntu/dis ... ackages.gz File has unexpected size (1343916 != 2228413). Mirror sync in progress? [IP: 192.115.211.70 80]
Hashes of expected file:
- Filesize:2228413 [weak]
- SHA512:40d24577e8e862ff30bd9d1f68df3be763258ce6a690f8daf5cb0aa12c363c14876813776f188a1a783ab2191b5e4f27ecfd454f20f2824c21e82f4e1facf0f1
- SHA256:b97a2c6067ebe3a2feb20940faa40a4598a18db722676cdbe3a7aa726165f14e
- SHA1:781a95f61fd759ebe2f2f3891e8057163d014c4d [weak]
- MD5Sum:feeebc70f5724b1bc2f242f75e9e02ca [weak]
Release file created at: Wed, 20 Mar 2019 14:20:14 +0000
E: Failed to fetch http://il.archive.ubuntu.com/ubuntu/dis ... ackages.gz
E: Some index files failed to download. They have been ignored, or old ones used instead.

I will try again later to see if the errors are resolved.
Nigel

the apt command is just a user-focused wrapper over apt-get and other related utilities, so I'd expect the two to behave similarly.
The error seems to be complaining about a mirror sync problem, as though you are trying to update in the middle of the repository mirror syncing it's repositories with the main repositories. You could maybe try using a different mirror, or just wait for the mirror to finish syncing.

some quick googling turned up: https://stackoverflow.com/questions/466 ... ected-size, which suggests you may have multiple entries in your /etc/apt/sources.list which may be confusing apt. (sharing the contents of that file may help with resolving the problem)

Hi, Nigel
Aldrik is right, you must provide the /etc/apt/sources.list in order to have an exact idea of what is happening.

You can also try to change the software sources to another mirror and refresh your /etc/apt/sources.list
I seems that the problem is on the following sources:
http://il.archive.ubuntu.com/ubuntu/dis ... ackages.gz
http://il.archive.ubuntu.com/ubuntu/dis ... ackages.gz

Regards,

Thanks for your replies and sorry it's taken me a while to post again.
I wanted to edit my
/etc/apt/sources.list
to delete the line:
http://il.archive.ubuntu.com/ubuntu bionic/main i386 Packages
but when trying sudo kwrite /etc/apt/sources.list, or sudo kate /etc/apt/sources.list, I get the following:
Executing KWrite with sudo is not possible due to unfixable security vulnerabilities.
Executing Kate with sudo is not possible due to unfixable security vulnerabilities.

So how do I edit my /etc/apt/sources.list ?
Yours,
Nigel

nigelridley wrote:Thanks for your replies and sorry it's taken me a while to post again.
I wanted to edit my
/etc/apt/sources.list
to delete the line:
http://il.archive.ubuntu.com/ubuntu bionic/main i386 Packages
but when trying sudo kwrite /etc/apt/sources.list, or sudo kate /etc/apt/sources.list, I get the following:
Executing KWrite with sudo is not possible due to unfixable security vulnerabilities.
Executing Kate with sudo is not possible due to unfixable security vulnerabilities.

So how do I edit my /etc/apt/sources.list ?
Yours,
Nigel

Just open Kwrite normally, then open and edit the file. When you save it, you will then prompt for your password.