diff --git a/README.html b/README.html
index 22b35422..8d69b6c5 100644
--- a/README.html
+++ b/README.html
@@ -1,17 +1,17 @@
 <!DOCTYPE html>
 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
 <head>
-<meta charset="utf-8"/>
+<meta charset="utf-8" />
+<meta name="generator" content="Docutils 0.20.1: https://docutils.sourceforge.io/" />
 <meta name="viewport" content="width=device-width, initial-scale=1" />
-<meta name="generator" content="Docutils 0.17.1: http://docutils.sourceforge.net/" />
 <title>PySpice : Simulate Electronic Circuit using Python and the Ngspice / Xyce Simulators</title>
 <style type="text/css">
 
 /* Minimal style sheet for the HTML output of Docutils.                    */
 /*                                                                         */
 /* :Author: Günter Milde, based on html4css1.css by David Goodger          */
-/* :Id: $Id: minimal.css 8642 2021-03-26 13:51:14Z milde $               */
-/* :Copyright: © 2015 Günter Milde.                                        */
+/* :Id: $Id: minimal.css 9079 2022-06-19 14:00:56Z milde $                                                               */
+/* :Copyright: © 2015, 2021 Günter Milde.                                  */
 /* :License: Released under the terms of the `2-Clause BSD license`_,      */
 /*    in short:                                                            */
 /*                                                                         */
@@ -23,11 +23,10 @@
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-/* .. _CSS2.1: http://www.w3.org/TR/CSS2                                  */
-/* .. _validates: http://jigsaw.w3.org/css-validator/validator$link       */
+/* This CSS3 stylesheet defines rules for Docutils elements without        */
+/* HTML equivalent. It is required to make the document semantics visible. */
+/*                                                                         */
+/* .. _validates: http://jigsaw.w3.org/css-validator/validator$link        */
 
 /* titles */
 p.topic-title,
@@ -52,8 +51,8 @@
 h1 + p.subtitle {
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-h2 + p.section-subtitle, a.toc-backref {
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+a.toc-backref {
+  color: inherit;
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@@ -85,13 +84,11 @@
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@@ -110,17 +107,20 @@
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+dl.option-list,
+dl.docinfo {
+  display: flow-root;
+}
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 dl.option-list > dt,
-dl.docinfo > dt,
-dl.footnote > dt,
-dl.citation > dt {
+dl.docinfo > dt {
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-  padding-right: 0.5em;
+  padding-right: 0.2em;
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 /* Offset for field content (corresponds to the --field-name-limit option) */
 dl.field-list > dd,
@@ -128,6 +128,12 @@
 dl.docinfo > dd {
   margin-left:  9em; /* ca. 14 chars in the test examples, fit all Docinfo fields */
 }
+/* start nested lists on new line */
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+dd > ul:first-child,
+dd > ol:first-child {
+  clear: left;
+}
 /* start field-body on a new line after long field names */
 dl.field-list > dd > *:first-child,
 dl.option-list > dd > *:first-child
@@ -136,11 +142,6 @@
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+
+.footnote, .citation { margin: 1em 0; } /* default paragraph skip (Firefox) */
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+
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+}
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+.citation > .label + p, .citation > .backrefs + p {
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+}
+
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+.backrefs > a { font-style: italic; }
+
+/* superscript footnotes */
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+  line-height: 1;
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-  font-weight: normal;
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+  /* hide brackets in display but leave for copy/paste */
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+  width: 0;
+  overflow: hidden;
+}
+[role="doc-noteref"].superscript + [role="doc-noteref"].superscript {
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   margin: 1em 2em;
+  border: thin solid;
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@@ -255,7 +276,7 @@
 
 /* Images are block-level by default in Docutils */
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@@ -270,7 +291,7 @@
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 /* :Author: Günter Milde, based on html4css1.css by David Goodger          */
-/* :Id: $Id: plain.css 8636 2021-03-19 00:23:33Z milde $                                                               */
+/* :Id: $Id: plain.css 9338 2023-04-08 21:08:47Z milde $                                                               */
 /* :Copyright: © 2015 Günter Milde.                                        */
 /* :License: Released under the terms of the `2-Clause BSD license`_,      */
 /*    in short:                                                            */
@@ -282,7 +303,7 @@
 /*    This file is offered as-is, without any warranty.                    */
 /*                                                                         */
 /* .. _2-Clause BSD license: http://www.spdx.org/licenses/BSD-2-Clause     */
-/* .. _CSS3: http://www.w3.org/TR/CSS3                                     */
+/* .. _CSS3: https://www.w3.org/Style/CSS/                                 */
 
 
 /* Document Structure */
@@ -292,9 +313,10 @@
 body {
   margin: 0;
   background-color: #dbdbdb;
+  --field-indent: 9em; /* default indent of fields in field lists */
 }
 main, footer, header {
-  line-height:1.3;
+  line-height:1.6;
   /* avoid long lines --> better reading */
   /* optimum is 45…75 characters/line <http://webtypography.net/2.1.2> */
   /* OTOH: lines should not be too short because of missing hyphenation, */
@@ -312,6 +334,21 @@
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 }
 
+/* Table of Contents */
+ul.auto-toc > li > p {
+  padding-left: 1em;
+  text-indent: -1em;
+}
+nav.contents ul {
+  padding-left: 1em;
+}
+main > nav.contents ul ul ul ul:not(.auto-toc) {
+  list-style-type: '\2B29\ ';
+}
+main > nav.contents ul ul ul ul ul:not(.auto-toc) {
+  list-style-type: '\2B1D\ ';
+}
+
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   width: 80%;
@@ -323,49 +360,56 @@
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 /* vertical space (parskip) */
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+p, ol, ul, dl, li,
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-/* (:last-child is new in CSS 3) */
-p:last-child  { margin-bottom: 0; }
 
 h1, h2, h3, h4, h5, h6,
-dl > dd {
+dd, details > p:last-child {
   margin-bottom: 0.5em;
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 /* Lists */
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-/* Separate list entries in compound lists */
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-
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 dd > ul:only-child, dd > ol:only-child { padding-left: 1em; }
 
 /* Description Lists */
 /* styled like in most dictionaries, encyclopedias etc. */
+dl.description {
+  display: flow-root;
+}
 dl.description > dt {
   font-weight: bold;
   clear: left;
   float: left;
   margin: 0;
   padding: 0;
-  padding-right: 0.5em;
+  padding-right: 0.3em;
+}
+dl.description > dd:after {
+  display: table;
+  content: "";
+  clear: left; /* clearfix for empty descriptions */
 }
 
 /* Field Lists */
 
+dl.field-list > dd,
+dl.docinfo > dd {
+  margin-left: var(--field-indent); /* adapted in media queries or HTML */
+}
+
 /* example for custom field-name width */
 dl.field-list.narrow > dd {
-  margin-left: 5em;
+  --field-indent: 5em;
 }
 /* run-in: start field-body on same line after long field names */
 dl.field-list.run-in > dd p {
@@ -374,8 +418,8 @@
 
 /* Bibliographic Fields */
 
-/* generally, bibliographic fields use special definition list dl.docinfo */
-/* but dedication and abstract are placed into "topic" divs */
+/* generally, bibliographic fields use dl.docinfo */
+/* but dedication and abstract are placed into divs */
 div.abstract p.topic-title {
   text-align: center;
 }
@@ -388,6 +432,10 @@
   font-style: normal;
 }
 
+/* disclosures */
+details { padding-left: 1em; }
+summary { margin-left: -1em; }
+
 /* Text Blocks */
 /* =========== */
 
@@ -397,14 +445,10 @@
   font-family: monospace;
 }
 
-/* Block Quotes */
-blockquote > table,
-div.topic > table {
-  margin-top: 0;
-  margin-bottom: 0;
-}
+/* Block Quotes and Topics */
+bockquote { margin: 1em 2em; }
 blockquote p.attribution,
-div.topic p.attribution {
+.topic p.attribution {
   text-align: right;
   margin-left: 20%;
 }
@@ -444,10 +488,9 @@
 /* ----------------------- */
 
 /* line on the left */
-dl.footnote {
-  padding-left: 1ex;
-  border-left: solid;
-  border-left-width: thin;
+.footnote-list {
+  border-left: solid thin;
+  padding-left: 0.25em;
 }
 
 /* Directives */
@@ -501,16 +544,19 @@
 aside.sidebar {
   width: 30%;
   max-width: 26em;
+  float: right;
+  clear: right;
   margin-left: 1em;
-  margin-right: -2%;
-  background-color: #ffffee;
+  margin-right: -1%;
+  background-color: #fffffa;
 }
 
+
 /* Code */
 pre.code { padding: 0.7ex }
 pre.code, code { background-color: #eeeeee }
 /* basic highlighting: for a complete scheme, see */
-/* http://docutils.sourceforge.net/sandbox/stylesheets/ */
+/* https://docutils.sourceforge.io/sandbox/stylesheets/ */
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 pre.code .keyword, code .keyword { color: #3B0D06; font-weight: bold }
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@@ -519,7 +565,14 @@
 pre.code .inserted, code .inserted { background-color: #A3D289}
 
 /* Math */
-/* styled separately (see math.css for math-output=HTML) */
+/* for math-output=MathML (for math-output=HTML, see math.css) */
+math .boldsymbol {
+  font-weight: bold;
+}
+mstyle.mathscr, mi.mathscr {
+  font-family: STIX, XITSMathJax_Script, rsfs10,
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+}
 
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@@ -530,6 +583,8 @@
 /* Inline Markup */
 /* ============= */
 
+sup, sub { line-height: 0.8; } /* do not add leading for lines with sup/sub */
+
 /* Inline Literals                                          */
 /* possible values: normal, nowrap, pre, pre-wrap, pre-line */
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@@ -542,7 +597,7 @@
 /* Internal Targets       */
 /*   span.target.internal */
 /* Footnote References    */
-/*   a.footnote-reference */
+/*   a[role="doc-noteref"] */
 /* Citation References    */
 /*   a.citation-reference */
 
@@ -574,10 +629,20 @@ <h1 class="title">PySpice : Simulate Electronic Circuit using Python and the Ngs
 <li><p><a class="reference external" href="https://sourceforge.net/p/ngspice/bugs">Ngspice Bug Tracker</a></p></li>
 <li><p><a class="reference external" href="https://xyce.sandia.gov">Xyce of Sandia National Laboratories</a></p></li>
 </ul>
-<section id="brief-notes">
-<h2>Brief Notes</h2>
-<p>Thanks to <a class="reference external" href="https://www.discourse.org">Discourse</a>, PySpice now has a <strong>Forum</strong> hosted at <a class="reference external" href="https://pyspice.discourse.group">https://pyspice.discourse.group</a></p>
+<section id="update">
+<h2>2024 Update</h2>
 <p><strong>Disclaimer: PySpice is developed on my free time actually, so I could be busy with other tasks and less reactive.</strong></p>
+<p>The free Discourse forum was closed some time ago due to a lack of activity.
+A HTML backup is stored in the directory <cite>pyspice-discourse-backup</cite>.</p>
+<p><strong>On HEAD</strong>
+* fixed the ngspice library loading for recent cffi
+* fixed simulation aborting due to a message from newer ngspice
+* fixes for Spice parser
+* added support for Pint unit library
+* implemented SpiceLibrary
+* code cleanup but must check for typo...</p>
+<!-- Brief Notes
+=========== -->
 <p>An issue was found with NgSpice Shared, we must <cite>setlocale(LC_NUMERIC, &quot;C&quot;);</cite> see <a class="reference external" href="https://sourceforge.net/p/ngspice/bugs/490/">https://sourceforge.net/p/ngspice/bugs/490/</a></p>
 </section>
 <section id="overview">
@@ -647,20 +712,20 @@ <h3>Vx.y.0 (wishes)</h3>
 <h3>V1.6.0 (development release)</h3>
 <ul>
 <li><p><strong>New Simulation API</strong></p>
-<pre class="code python literal-block"><code><span class="comment single"># build a circuit</span>
-
-<span class="comment single"># instantiate a simulator</span>
-<span class="name">simulator</span> <span class="operator">=</span> <span class="name">Simulator</span><span class="operator">.</span><span class="name">factory</span><span class="punctuation">()</span>
-<span class="comment single"># or</span>
-<span class="name">simulator</span> <span class="operator">=</span> <span class="name">Simulator</span><span class="operator">.</span><span class="name">factory</span><span class="punctuation">(</span><span class="name">simulator</span><span class="operator">=</span><span class="literal string single">'ngspice'</span><span class="punctuation">)</span>
-<span class="comment single"># same as</span>
-<span class="name">simulator</span> <span class="operator">=</span> <span class="name">Simulator</span><span class="operator">.</span><span class="name">factory</span><span class="punctuation">(</span><span class="name">simulator</span><span class="operator">=</span><span class="literal string single">'ngspice-shared'</span><span class="punctuation">)</span>
-
-<span class="comment single"># create a simulation, it corresponds to the Spice code part with lines starting with &quot;.something ...&quot;</span>
-<span class="name">simulation</span> <span class="operator">=</span> <span class="name">simulator</span><span class="operator">.</span><span class="name">simulation</span><span class="punctuation">(</span><span class="name">circuit</span><span class="punctuation">,</span> <span class="name">temperature</span><span class="operator">=</span><span class="literal number integer">25</span><span class="punctuation">,</span> <span class="name">nominal_temperature</span><span class="operator">=</span><span class="literal number integer">25</span><span class="punctuation">)</span>
-<span class="comment single"># define an analysis and run it</span>
-<span class="name">analysis</span> <span class="operator">=</span> <span class="name">simulation</span><span class="operator">.</span><span class="name">transient</span><span class="punctuation">(</span><span class="name">step_time</span><span class="operator">=</span><span class="name">ac_line</span><span class="operator">.</span><span class="name">period</span><span class="operator">/</span><span class="literal number integer">200</span><span class="punctuation">,</span> <span class="name">end_time</span><span class="operator">=</span><span class="name">ac_line</span><span class="operator">.</span><span class="name">period</span><span class="operator">*</span><span class="literal number integer">50</span><span class="punctuation">,</span> <span class="name">log_desk</span><span class="operator">=</span><span class="keyword constant">True</span><span class="punctuation">)</span>
-<span class="comment single"># analysis is now Pickable</span></code></pre>
+<pre class="code python literal-block"><code><span class="comment single"># build a circuit</span><span class="whitespace">
+
+</span><span class="comment single"># instantiate a simulator</span><span class="whitespace">
+</span><span class="name">simulator</span> <span class="operator">=</span> <span class="name">Simulator</span><span class="operator">.</span><span class="name">factory</span><span class="punctuation">()</span><span class="whitespace">
+</span><span class="comment single"># or</span><span class="whitespace">
+</span><span class="name">simulator</span> <span class="operator">=</span> <span class="name">Simulator</span><span class="operator">.</span><span class="name">factory</span><span class="punctuation">(</span><span class="name">simulator</span><span class="operator">=</span><span class="literal string single">'ngspice'</span><span class="punctuation">)</span><span class="whitespace">
+</span><span class="comment single"># same as</span><span class="whitespace">
+</span><span class="name">simulator</span> <span class="operator">=</span> <span class="name">Simulator</span><span class="operator">.</span><span class="name">factory</span><span class="punctuation">(</span><span class="name">simulator</span><span class="operator">=</span><span class="literal string single">'ngspice-shared'</span><span class="punctuation">)</span><span class="whitespace">
+
+</span><span class="comment single"># create a simulation, it corresponds to the Spice code part with lines starting with &quot;.something ...&quot;</span><span class="whitespace">
+</span><span class="name">simulation</span> <span class="operator">=</span> <span class="name">simulator</span><span class="operator">.</span><span class="name">simulation</span><span class="punctuation">(</span><span class="name">circuit</span><span class="punctuation">,</span> <span class="name">temperature</span><span class="operator">=</span><span class="literal number integer">25</span><span class="punctuation">,</span> <span class="name">nominal_temperature</span><span class="operator">=</span><span class="literal number integer">25</span><span class="punctuation">)</span><span class="whitespace">
+</span><span class="comment single"># define an analysis and run it</span><span class="whitespace">
+</span><span class="name">analysis</span> <span class="operator">=</span> <span class="name">simulation</span><span class="operator">.</span><span class="name">transient</span><span class="punctuation">(</span><span class="name">step_time</span><span class="operator">=</span><span class="name">ac_line</span><span class="operator">.</span><span class="name">period</span><span class="operator">/</span><span class="literal number integer">200</span><span class="punctuation">,</span> <span class="name">end_time</span><span class="operator">=</span><span class="name">ac_line</span><span class="operator">.</span><span class="name">period</span><span class="operator">*</span><span class="literal number integer">50</span><span class="punctuation">,</span> <span class="name">log_desk</span><span class="operator">=</span><span class="keyword constant">True</span><span class="punctuation">)</span><span class="whitespace">
+</span><span class="comment single"># analysis is now Pickable</span></code></pre>
 </li>
 <li><p>Simulation output is now Pickable</p></li>
 <li><p>The <strong>Spice parser</strong> was rewritten from scratch using the <a class="reference external" href="https://www.dabeaz.com/ply">PLY</a>
diff --git a/README.rst b/README.rst
index a891e872..5151a729 100644
--- a/README.rst
+++ b/README.rst
@@ -109,13 +109,26 @@
 * `Ngspice Bug Tracker <https://sourceforge.net/p/ngspice/bugs>`_
 * `Xyce of Sandia National Laboratories <https://xyce.sandia.gov>`_
 
-Brief Notes
+2024 Update
 ===========
 
-Thanks to `Discourse <https://www.discourse.org>`_, PySpice now has a **Forum** hosted at https://pyspice.discourse.group
-
 **Disclaimer: PySpice is developed on my free time actually, so I could be busy with other tasks and less reactive.**
 
+The free Discourse forum was closed some time ago due to a lack of activity.
+A HTML backup is stored in the directory `pyspice-discourse-backup`.
+
+**On HEAD**
+* fixed the ngspice library loading for recent cffi
+* fixed simulation aborting due to a message from newer ngspice
+* fixes for Spice parser
+* added support for Pint unit library
+* implemented SpiceLibrary
+* code cleanup but must check for typo...
+
+..
+    Brief Notes
+    ===========
+
 An issue was found with NgSpice Shared, we must `setlocale(LC_NUMERIC, "C");` see https://sourceforge.net/p/ngspice/bugs/490/
 
 Overview
diff --git a/README.txt b/README.txt
index 2ae0652b..e6763a20 100644
--- a/README.txt
+++ b/README.txt
@@ -33,13 +33,26 @@
 * `Ngspice Bug Tracker <https://sourceforge.net/p/ngspice/bugs>`_
 * `Xyce of Sandia National Laboratories <https://xyce.sandia.gov>`_
 
-Brief Notes
+2024 Update
 ===========
 
-Thanks to `Discourse <https://www.discourse.org>`_, PySpice now has a **Forum** hosted at https://pyspice.discourse.group
-
 **Disclaimer: PySpice is developed on my free time actually, so I could be busy with other tasks and less reactive.**
 
+The free Discourse forum was closed some time ago due to a lack of activity.
+A HTML backup is stored in the directory `pyspice-discourse-backup`.
+
+**On HEAD**
+* fixed the ngspice library loading for recent cffi
+* fixed simulation aborting due to a message from newer ngspice
+* fixes for Spice parser
+* added support for Pint unit library
+* implemented SpiceLibrary
+* code cleanup but must check for typo...
+
+..
+    Brief Notes
+    ===========
+
 An issue was found with NgSpice Shared, we must `setlocale(LC_NUMERIC, "C");` see https://sourceforge.net/p/ngspice/bugs/490/
 
 Overview
