export PATH=/home/john/perl5/bin:$PATH
[download]

Sorry it's taken me so long to respond. Here's the perl -V output

Summary of my perl5 (revision 5 version 28 subversion 2) configuration
+:
   
  Platform:
    osname=linux
    osvers=4.20.13-200.fc29.x86_64
    archname=x86_64-linux-thread-multi
    uname='linux buildhw-06.phx2.fedoraproject.org 4.20.13-200.fc29.x8
+6_64 #1 smp wed feb 27 19:42:55 utc 2019 x86_64 x86_64 x86_64 gnulinu
+x '
    config_args='-des -Doptimize=none -Dccflags=-O2 -g -pipe -Wall -We
+rror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTION
+S -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=
+/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/re
+dhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fs
+tack-clash-protection -fcf-protection -Dldflags=-Wl,-z,relro   -Wl,-z
+,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -Dccdlflags=-Wl,--
+enable-new-dtags -Wl,-z,relro   -Wl,-z,now -specs=/usr/lib/rpm/redhat
+/redhat-hardened-ld -Dlddlflags=-shared -Wl,-z,relro   -Wl,-z,now -sp
+ecs=/usr/lib/rpm/redhat/redhat-hardened-ld -Dshrpdir=/usr/lib64 -DDEB
+UGGING=-g -Dversion=5.28.2 -Dmyhostname=localhost -Dperladmin=root@lo
+calhost -Dcc=gcc -Dcf_by=Red Hat, Inc. -Dprefix=/usr -Dvendorprefix=/
+usr -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl5 -Dsitear
+ch=/usr/local/lib64/perl5 -Dprivlib=/usr/share/perl5 -Dvendorlib=/usr
+/share/perl5/vendor_perl -Darchlib=/usr/lib64/perl5 -Dvendorarch=/usr
+/lib64/perl5/vendor_perl -Darchname=x86_64-linux-thread-multi -Dlibpt
+h=/usr/local/lib64 /lib64 /usr/lib64 -Duseshrplib -Dusethreads -Dusei
+threads -Dusedtrace=/usr/bin/dtrace -Duselargefiles -Dd_semctl_semun 
+-Di_db -Ui_ndbm -Di_gdbm -Di_shadow -Di_syslog -Dman3ext=3pm -Duseper
+lio -Dinstallusrbinperl=n -Ubincompat5005 -Uversiononly -Dpager=/usr/
+bin/less -isr -Dd_gethostent_r_proto -Ud_endhostent_r_proto -Ud_setho
+stent_r_proto -Ud_endprotoent_r_proto -Ud_setprotoent_r_proto -Ud_end
+servent_r_proto -Ud_setservent_r_proto -Dscriptdir=/usr/bin -Dusesite
+customize -Duse64bitint'
    hint=recommended
    useposix=true
    d_sigaction=define
    useithreads=define
    usemultiplicity=define
    use64bitint=define
    use64bitall=define
    uselongdouble=undef
    usemymalloc=n
    default_inc_excludes_dot=define
    bincompat5005=undef
  Compiler:
    cc='gcc'
    ccflags ='-D_REENTRANT -D_GNU_SOURCE -O2 -g -pipe -Wall -Werror=fo
+rmat-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexc
+eptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/li
+b/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-an
+nobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-cl
+ash-protection -fcf-protection -fwrapv -fno-strict-aliasing -I/usr/lo
+cal/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64'
    optimize='  -g'
    cppflags='-D_REENTRANT -D_GNU_SOURCE -O2 -g -pipe -Wall -Werror=fo
+rmat-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexc
+eptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/li
+b/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-an
+nobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-cl
+ash-protection -fcf-protection -fwrapv -fno-strict-aliasing -I/usr/lo
+cal/include'
    ccversion=''
    gccversion='8.3.1 20190223 (Red Hat 8.3.1-2)'
    gccosandvers=''
    intsize=4
    longsize=8
    ptrsize=8
    doublesize=8
    byteorder=12345678
    doublekind=3
    d_longlong=define
    longlongsize=8
    d_longdbl=define
    longdblsize=16
    longdblkind=3
    ivtype='long'
    ivsize=8
    nvtype='double'
    nvsize=8
    Off_t='off_t'
    lseeksize=8
    alignbytes=8
    prototype=define
  Linker and Libraries:
    ld='gcc'
    ldflags ='-Wl,-z,relro -Wl,-z,now -specs=/usr/lib/rpm/redhat/redha
+t-hardened-ld -fstack-protector-strong -L/usr/local/lib'
    libpth=/usr/local/lib64 /lib64 /usr/lib64 /usr/local/lib /usr/lib 
+/lib/../lib64 /usr/lib/../lib64 /lib
    libs=-lpthread -lresolv -lgdbm -ldb -ldl -lm -lcrypt -lutil -lc -l
+gdbm_compat
    perllibs=-lpthread -lresolv -ldl -lm -lcrypt -lutil -lc
    libc=libc-2.28.so
    so=so
    useshrplib=true
    libperl=libperl.so
    gnulibc_version='2.28'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs
    dlext=so
    d_dlsymun=undef
    ccdlflags='-Wl,--enable-new-dtags -Wl,-z,relro -Wl,-z,now -specs=/
+usr/lib/rpm/redhat/redhat-hardened-ld'
    cccdlflags='-fPIC'
    lddlflags='-lpthread -shared -Wl,-z,relro -Wl,-z,now -specs=/usr/l
+ib/rpm/redhat/redhat-hardened-ld -L/usr/local/lib -fstack-protector-s
+trong'


Characteristics of this binary (from libperl): 
  Compile-time options:
    HAS_TIMES
    MULTIPLICITY
    PERLIO_LAYERS
    PERL_COPY_ON_WRITE
    PERL_DONT_CREATE_GVSV
    PERL_IMPLICIT_CONTEXT
    PERL_MALLOC_WRAP
    PERL_OP_PARENT
    PERL_PRESERVE_IVUV
    USE_64_BIT_ALL
    USE_64_BIT_INT
    USE_ITHREADS
    USE_LARGE_FILES
    USE_LOCALE
    USE_LOCALE_COLLATE
    USE_LOCALE_CTYPE
    USE_LOCALE_NUMERIC
    USE_LOCALE_TIME
    USE_PERLIO
    USE_PERL_ATOF
    USE_REENTRANT_API
    USE_SITECUSTOMIZE
  Locally applied patches:
    Fedora Patch1: Removes date check, Fedora/RHEL specific
    Fedora Patch2: support for libdir64
    Fedora Patch3: use libresolv instead of libbind
    Fedora Patch4: USE_MM_LD_RUN_PATH
    Fedora Patch5: Provide MM::maybe_command independently (bug #11294
+43)
    Fedora Patch6: Dont run one io test due to random builder failures
    Fedora Patch8: Define SONAME for libperl.so
    Fedora Patch9: Install libperl.so to -Dshrpdir value
    Fedora Patch10: Document Math::BigInt::CalcEmu requires Math::BigI
+nt (CPAN RT#85015)
    Fedora Patch11: Make *DBM_File desctructors thread-safe (RT#61912)
    Fedora Patch12: Replace EU::MakeMaker dependency with EU::MM::Util
+s in IPC::Cmd (bug #1129443)
    Fedora Patch13: Fix executing arybase::_tie_it() in Safe compartem
+ent (RT#131588)
    Fedora Patch14: Link XS modules to pthread library to fix linking 
+with -z defs
    Fedora Patch17: Fix printing a warning about a wide character when
+ matching a regular expression while ISO-8859-1 locale is in effect
    Fedora Patch18: Fix invoking a check for wide characters while ISO
+-8859-1 locale is in effect
    Fedora Patch20: Fix build conditions in locale.c
    Fedora Patch21: Fix a file descriptor leak in in-place edits (RT#1
+33314)
    Fedora Patch23: Fix a buffer overrun in deprecated S_is_utf8_commo
+n()
    Fedora Patch24: Fix a time race in Time-HiRes/t/itimer.t test
    Fedora Patch26: Fix Time::Piece to handle objects in overloaded me
+thods correctly
    Fedora Patch27: Fix an assignment to a lexical variable in multico
+ncatenation expressions (RT#133441)
    Fedora Patch28: Fix a spurious warning about uninitialized value i
+n warn (RT#132683)
    Fedora Patch30: Pass the correct CFLAGS to dtrace
    Fedora Patch33: Fix PathTools tests to cope with ESTALE error (RT#
+133534)
    Fedora Patch34: Fix an undefined behaviour in S_hv_delete_common()
    Fedora Patch38: Fix compiling regular expressions that contain bot
+h compile- and run-time compiled code blocks (RT#133687)
    Fedora Patch39: Adjust tests to gdbm-1.15 (RT#133295)
    Fedora Patch44: Fix reporting a line number for non-terminated pro
+totypes (RT#133524)
    Fedora Patch45: Fix first eof() return value (RT#133721)
    Fedora Patch49: Prevent long jumps from clobbering local variables
+ (RT#133575)
    Fedora Patch50: Fix a mismatch with a case-insesitive regular expr
+ession on a text with ligatures (RT#133756)
    Fedora Patch53: Fix setting magic when changing $^R (RT#133782)
    Fedora Patch54: Fix a race when loading XS modules
    Fedora Patch56: Fix a leak when compiling a typed hash dereference
    Fedora Patch58: Fix a buffer overread when handling a scope error 
+in qr/\(?{/ (RT#133879)
    Fedora Patch59: Fix a buffer overread when parsing a regular expre
+ssion with an unknown character name (RT#133880)
    Fedora Patch60: Fix mbstate_t initialization in POSIX::mblen (RT#1
+33928)
    Fedora Patch61: Fix a memory leak when cloning a regular expressio
+n
    Fedora Patch62: Fix a memory leak when spawning threads in a BEGIN
+ phase
    Fedora Patch63: Fix a memory leak when assigning a regular express
+ion to a non-copy-on-write string
    Fedora Patch64: Fix a memory leak when assignig to a localized ${^
+WARNING_BITS}
    Fedora Patch65: Fix a memory leak when parsing misindented here-do
+cuments
    Fedora Patch66: Fix a memory leak in package name lookup (RT#13397
+7)
    Fedora Patch68: Fix a memory leak when deletion in a tied hash die
+s
    Fedora Patch69: Fix a crash when matching case insensitively (RT#1
+33892)
    Fedora Patch70: Fix a memory leak when warning about malformed UTF
+-8 string
    Fedora Patch200: Link XS modules to libperl.so with EU::CBuilder o
+n Linux
    Fedora Patch201: Link XS modules to libperl.so with EU::MM on Linu
+x
  Built under linux
  Compiled at Apr 23 2019 08:44:49
  %ENV:
    PERL5LIB="/home/john/perl5/lib/perl5:/home/john/perl5/lib/perl5"
    PERL_LOCAL_LIB_ROOT="/home/john/perl5:/home/john/perl5"
    PERL_MB_OPT="--install_base "/home/john/perl5""
    PERL_MM_OPT="INSTALL_BASE=/home/john/perl5"
  @INC:
    /home/john/perl5/lib/perl5/x86_64-linux-thread-multi
    /home/john/perl5/lib/perl5
    /home/john/perl5/lib/perl5/x86_64-linux-thread-multi
    /home/john/perl5/lib/perl5
    /usr/local/lib64/perl5
    /usr/local/share/perl5
    /usr/lib64/perl5/vendor_perl
    /usr/share/perl5/vendor_perl
    /usr/lib64/perl5
    /usr/share/perl5
[download]

And here's the $PATH:

/home/john/perl5/bin:./:/home/john/perl5/bin:./:/usr/lib64/qt-3.3/bin:
+/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/home/john/bin
+:/opt/go/bin:/home/john/.local/bin:/home/john/bin:/home/john/bin:/opt
+/go/bin
[download]

Thanks

Here's the perl -V output

It's quite different to what I was expecting
That looks like a system perl, but it's in your home directory. How does that come about ?
It also seems odd to me that an upgrade from Fedora 28 to Fedora 29 should touch anything that's in your home directory - yet it apparently has. (Not that I'm expert in linux in general or fedora in particular).

Anyway - it does indeed demonstrate that you need to rebuild XML::Parser, as already recommended by others.
Maybe cpan -fi XML::Parser will achieve that.

Cheers,
Rob

Thanks for the quick reply. When I tried to recompile (using the cpan command "install XML::Parser", I got:

XML::Parser is up to date (2.44)

I am indeed running the v5.28.2 verions of Perl. Should I do something different to recompile XML::Parser?

Try cpanm -U XML::Parser. That'll prompt you to remove the distribution. After that's done, try reinstalling as normal.

If you do not have perlbrew installed then this is a good time to install it. It is really simple to install and even simpler to tell it to fetch a perl you want, compile it (itself, not you) and switch to using it.

In this way you leave system perl alone. There are a lot of system processes which depend on perl and possibly specific perl version. If you upgrade a package because a user needs it, then that system process can break. If you upgrade as root you override already existing versions. If you upgrade/install as user in your local dirs then the probability of damage is much less but you then depending on @INC and the paths order, you get this "unexplained" behaviour.

The benefits of perlbrew (or any other similar "alternatives" system) are obvious and the procedure is painless, as it is the learning curve (none basically).

If you must debug this issue, then try to get more information:

and finally find any Expat installations (may take some time):

Seconding this advice. The effort is more worth it when you're not scrambling because your application doesn't break when the OS' perl gets changed underneath it because the corporate IT people pushed a newer package to your systems without consulting you.

Not that I speak from experience here or anything . . . *cough*

The cake is a lie.
The cake is a lie.
The cake is a lie.

I am at the moment starting some fresh fedora install and I am doing just that with the additional twist that I want perlbrew-managed perls to be installed by superuser(=root) so that all users can use them without each installing their own. Additionally I want root to install a good deal of common modules (e.g. LWP) for all users. After that, if users need to install obscure modules in their own private/home dirs, it is up to them. Or they ask superuser to install it for everybody in public dir.

I have found that this setup entails some danger.

Because I do not want root to have in their login/startup script all those perlbrew-related variables. Perhaps that's a purist view but I opted for creating a script for root to use whenever is going to need to do perlbrew-housekeeping and not having that same commands in root's .bashrc. Something like:

#!/bin/sh
# this is bin/use-perlbrew.sh (not part of ~/.bashrc)
export PERLBREW_ROOT=/opt/perlbrew
export PERLBREW_HOME=${HOME}/.perlbrew
source ${PERLBREW_ROOT}/etc/bashrc
CMD="perlbrew use perl-5.30.0"
echo "$0 : executing: ${CMD}"
eval ${CMD}
if [ $? -ne 0 ]; then echo "$0 : command has failed ${CMD}"; exit 1; f
+i
[download]

So, on login, root uses system perl and does not know about any perlbrew stuff. If root has to install perlbrew-wise modules then runs above script first (EDIT: via source ~/bin/use-perlbrew.sh). I find this cleaner than staffing root's .bashrc with tom, dick and harry.

I am aware that perlbrew can manage the system perl as well with just a symlink - no need of re-installing it (thanks to https://stackoverflow.com/questions/25188575/switching-to-the-system-perl-using-perlbrew). So one can suggest adding the perlbrew variables+source in root's .bashrc and immediately after that add perlbrew use system.

I suspect my dislike of that is cargo-culting. Anyone knows better? (I think I will SOPW this)

45 min EDIT: gaining root access via plain su inherits all env vars from current shell. Which includes all the perlbrew variables the calling user had. su --login stops that and is the proper way to gain root access if not doing it from the login screen.