私のDebianシステム（Raspian Raspberry Pi）にはいくつかのパッケージがあります。試してsudo apt-get dist-upgradeみましたがアップグレードできませんでした。
$ sudo apt-get upgrade -y
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages have been kept back:
libalgorithm-diff-xs-perl libdbd-mysql-perl libdbi-perl libfile-fcntllock-perl
liblocale-gettext-perl libnet-libidn-perl libnet-ssleay-perl
libterm-readkey-perl libtext-charwidth-perl libtext-iconv-perl
libtext-soundex-perl
0 upgraded, 0 newly installed, 0 to remove and 11 not upgraded.
$ sudo apt-get dist-upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
パッケージは保管されません。以下に出力はありません。
$ dpkg --get-selections | grep hold
これらのパッケージがブロックされる原因は何ですか？どのようにアップグレードしますか？
答え1
jordanmのコメントによると、依存関係（perlベース）がテストリポジトリから欠落している可能性があります。数日後にもう一度試してみましたが、効果があるようです。
$ sudo apt-get dist-upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages will be REMOVED:
libperl5.18
The following NEW packages will be installed:
docutils-common docutils-doc libalgorithm-c3-perl libcgi-pm-perl libclass-c3-perl
libclass-c3-xs-perl libdata-optlist-perl libdata-section-perl libfcgi-perl
libmodule-build-perl libmodule-signature-perl libmro-compat-perl
libpackage-constants-perl libparams-util-perl libperl5.20 libpod-readme-perl
libregexp-common-perl libsoftware-license-perl libsub-exporter-perl
libsub-install-perl libtext-template-perl libwebp5 libwebpdemux1 libwebpmux1
php-aws-sdk-doc php-guzzle-doc python-docutils python-guzzle-sphinx-theme
python-jinja2 python-markupsafe python-pil python-pygments python-roman
python-sphinx sphinx-common sphinx-doc
The following packages will be upgraded:
elinks libalgorithm-diff-xs-perl libdbd-mysql-perl libdbi-perl
libfile-fcntllock-perl liblocale-gettext-perl libnet-libidn-perl
libnet-ssleay-perl libterm-readkey-perl libtext-charwidth-perl libtext-iconv-perl
libtext-soundex-perl perl perl-base perl-modules php-aws-sdk php-guzzle
17 upgraded, 36 newly installed, 1 to remove and 0 not upgraded.
Need to get 0 B/15.0 MB of archives.
After this operation, 25.0 MB of additional disk space will be used.
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