How to Create Different PDF Versions in C#

Curtis Chau

Updated: August 2, 2026

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  # How to Create Different PDF Versions in C&#35; IronPDF automatically manages PDF version selection based on document features, choosing versions from 1.4 to 1.7 to ensure compatibility while preserving functionality. This seamless process handles everything from simple HTML conversions (typically PDF 1.4) to complex document merging (PDF 1.7 standard). When working with [PDF from HTML String](https://ironpdf.com/how-to/html-string-to-pdf/) conversions, IronPDF intelligently determines the appropriate version based on your content's requirements. *as-heading:2(Quickstart: Create Different PDF Versions in C#)* <div class="hsg-featured-snippet"> <ol> <li><a class="js-modal-open" data-modal-id="trial-license-after-download" href="https://www.nuget.org/packages/IronPdf/">Download <code>IronPdf</code> from NuGet</a></li> <li>Instantiate <code>ChromePdfRenderer</code></li> <li>Use <code>RenderHtmlAsPdf</code> method to render HTML</li> <li>Save and export the PDF document</li> <li>Verify the PDF version</li> </ol> </div> ```cs :title=Quickstart Example // Create a simple PDF using IronPDF - automatically selects version 1.4 using IronPdf; var renderer = new ChromePdfRenderer(); var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>"); pdf.SaveAs("hello-world.pdf"); ``` <br class="clear" /> ## How Do I Create a PDF Version 1.4 Document? IronPDF supports all PDF versions from 1.2 to 1.7. When converting HTML to PDF, IronPDF automatically selects the lowest version offered by the Chromium engine, ranging from PDF 1.4 to PDF 1.6, to maximize compatibility. This behavior matches what you'll find when [exporting different PDF versions](https://ironpdf.com/how-to/pdf-versions/) in various applications. Most conversions result in PDF 1.4. PDF 1.4 features transparency support, enabling modern graphic designs while maintaining broad compatibility. In this example, we'll convert an HTML string to PDF using IronPDF to demonstrate this behavior. This approach works seamlessly whether you're creating PDFs from [HTML files](https://ironpdf.com/how-to/html-file-to-pdf/), [URLs](https://ironpdf.com/how-to/url-to-pdf/), or [ASPX pages](https://ironpdf.com/how-to/aspx-to-pdf/). ### What Code Do I Need to Generate PDF 1.4? ```cs :path=/static-assets/pdf/content-code-examples/how-to/pdf-version-standard.cs ``` IronPDF's intelligent version selection shines here. For basic HTML content without advanced features, it defaults to PDF 1.4, ensuring your documents work across the widest range of PDF viewers and applications. This automatic selection eliminates manual version configuration in most scenarios. ### What Does the PDF 1.4 Output Look Like? <iframe loading="lazy" src="/static-assets/pdf/how-to/pdf-versions/pdf-standard.pdf" width="100%" height="400px"> </iframe> <div class="content-img-align-center"> <div class="center-image-wrapper"> <img src="/static-assets/pdf/how-to/pdf-versions/pdf-1.4-version.webp" alt="PDF properties dialog showing IronPDF v2025.9.18 as producer and PDF version 1.4 (Acrobat 5.x)" class="img-responsive add-shadow" /> </div> </div> As shown, IronPDF chose the lowest version from its range (PDF 1.4) to ensure compatibility. This version supports essential features like font embedding, encryption, and basic forms while maintaining excellent compatibility with older PDF readers. <hr /> ## How Do I Create a PDF Version 1.7 Document? IronPDF automatically generates PDF 1.7 (the international standard) when merging documents to ensure maximum compatibility. Since source PDFs may use different versions and features, defaulting to the comprehensive 1.7 standard ensures all original elements are preserved without data loss. This is crucial when [merging or splitting PDFs](https://ironpdf.com/how-to/merge-or-split-pdfs/) from various sources. PDF version 1.7 became the ISO standard (ISO 32000-1:2008) and includes advanced features: - Enhanced security and encryption options - 3D content support - Advanced transparency blending modes - Improved accessibility features - Better Unicode support for [international languages](https://ironpdf.com/how-to/utf-8/) ### What Code Do I Need for Merging PDFs to Version 1.7? ```cs :path=/static-assets/pdf/content-code-examples/how-to/merge-or-split-pdfs-merge.cs ``` This merging functionality is essential when combining documents from different sources or when you need to [add, copy, or delete PDF pages](https://ironpdf.com/how-to/add-copy-delete-pages-pdf/). The resulting PDF 1.7 document ensures all features from both source documents are preserved. ### Why Does IronPDF Use Version 1.7 for Merged Documents? <iframe loading="lazy" src="/static-assets/pdf/how-to/pdf-versions/pdf-merged.pdf" width="100%" height="400px"> </iframe> <div class="content-img-align-center"> <div class="center-image-wrapper"> <img src="/static-assets/pdf/how-to/pdf-versions/pdf-1.7-version.webp" alt="PDF properties showing IronPDF v2025.9.18 as producer and PDF version 1.7 (Acrobat 8.x compatibility)" class="img-responsive add-shadow" /> </div> </div> IronPDF generated a 1.7 version PDF by merging the two PDFs. This ensures: 1. **Universal Compatibility:** `PDF 1.7` is supported by all modern PDF readers and browsers 2. **Feature Preservation:** All advanced features from source documents are maintained 3. **Future-Proofing:** As the ISO standard, `PDF 1.7` ensures long-term document accessibility 4. **Enhanced Security:** Support for advanced [PDF permissions and passwords](https://ironpdf.com/how-to/pdf-permissions-passwords/) ## Advanced PDF Version Considerations When working with PDF versions in IronPDF, several factors influence automatic version selection: ### Content Complexity Simple HTML with basic text and images typically results in PDF 1.4, while documents containing JavaScript, forms, or multimedia content may trigger higher versions. When [executing custom JavaScript](https://ironpdf.com/how-to/javascript-to-pdf/) in your PDFs, IronPDF may select a higher version to support these interactive features. ### Feature Requirements Certain features require specific PDF versions: - **PDF 1.4:** Basic transparency, font embedding - **PDF 1.5:** Layers, object streams - **PDF 1.6:** OpenType fonts, 3D annotations - **PDF 1.7:** Enhanced security, package/portfolio features ### Compliance and Standards For archival purposes, you might need specific versions. IronPDF supports creating [PDF/A format documents](https://ironpdf.com/how-to/pdfa/) for long-term preservation, which have their own version requirements based on the PDF/A level chosen. ### Performance Optimization Different PDF versions have varying file sizes and processing requirements. PDF 1.4 documents are generally smaller and process faster, making them ideal for high-volume applications. Learn more about [PDF compression](https://ironpdf.com/how-to/pdf-compression/) techniques to optimize your documents. By understanding these version differences and letting IronPDF handle selection automatically, you ensure your PDFs maintain the perfect balance between compatibility, features, and performance for your specific use case.

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IronPDF automatically manages PDF version selection based on document features, choosing versions from 1.4 to 1.7 to ensure compatibility while preserving functionality. This seamless process handles everything from simple HTML conversions (typically PDF 1.4) to complex document merging (PDF 1.7 standard). When working with PDF from HTML String conversions, IronPDF intelligently determines the appropriate version based on your content's requirements.

How Do I Create a PDF Version 1.4 Document?

IronPDF supports all PDF versions from 1.2 to 1.7. When converting HTML to PDF, IronPDF automatically selects the lowest version offered by the Chromium engine, ranging from PDF 1.4 to PDF 1.6, to maximize compatibility. This behavior matches what you'll find when exporting different PDF versions in various applications.

Most conversions result in PDF 1.4. PDF 1.4 features transparency support, enabling modern graphic designs while maintaining broad compatibility. In this example, we'll convert an HTML string to PDF using IronPDF to demonstrate this behavior. This approach works seamlessly whether you're creating PDFs from HTML files, URLs, or ASPX pages.

What Code Do I Need to Generate PDF 1.4?

using IronPdf;

// Instantiate Renderer
var renderer = new ChromePdfRenderer();

// Render simple HTML to PDF
var pdf = renderer.RenderHtmlAsPdf("<p> Hello World!</p>");

// Save as PDF file, IronPDF automatically outputs to the PDF 1.4 standard
pdf.SaveAs("output.pdf");

using IronPdf;

// Instantiate Renderer
var renderer = new ChromePdfRenderer();

// Render simple HTML to PDF
var pdf = renderer.RenderHtmlAsPdf("<p> Hello World!</p>");

// Save as PDF file, IronPDF automatically outputs to the PDF 1.4 standard
pdf.SaveAs("output.pdf");

Imports IronPdf

' Instantiate Renderer
Dim renderer As New ChromePdfRenderer()

' Render simple HTML to PDF
Dim pdf = renderer.RenderHtmlAsPdf("<p> Hello World!</p>")

' Save as PDF file, IronPDF automatically outputs to the PDF 1.4 standard
pdf.SaveAs("output.pdf")

Imports IronPdf

' Instantiate Renderer
Dim renderer As New ChromePdfRenderer()

' Render simple HTML to PDF
Dim pdf = renderer.RenderHtmlAsPdf("<p> Hello World!</p>")

' Save as PDF file, IronPDF automatically outputs to the PDF 1.4 standard
pdf.SaveAs("output.pdf")

IronPDF's intelligent version selection shines here. For basic HTML content without advanced features, it defaults to PDF 1.4, ensuring your documents work across the widest range of PDF viewers and applications. This automatic selection eliminates manual version configuration in most scenarios.

What Does the PDF 1.4 Output Look Like?

As shown, IronPDF chose the lowest version from its range (PDF 1.4) to ensure compatibility. This version supports essential features like font embedding, encryption, and basic forms while maintaining excellent compatibility with older PDF readers.

How Do I Create a PDF Version 1.7 Document?

IronPDF automatically generates PDF 1.7 (the international standard) when merging documents to ensure maximum compatibility. Since source PDFs may use different versions and features, defaulting to the comprehensive 1.7 standard ensures all original elements are preserved without data loss. This is crucial when merging or splitting PDFs from various sources.

PDF version 1.7 became the ISO standard (ISO 32000-1:2008) and includes advanced features:

• Enhanced security and encryption options
• 3D content support
• Advanced transparency blending modes
• Improved accessibility features
• Better Unicode support for international languages

What Code Do I Need for Merging PDFs to Version 1.7?

using IronPdf;

// Two paged PDF
const string html_a =
    @"<p> [PDF_A] </p>
    <p> [PDF_A] 1st Page </p>
    <div style = 'page-break-after: always;' ></div>
    <p> [PDF_A] 2nd Page</p>";

// Two paged PDF
const string html_b =
    @"<p> [PDF_B] </p>
    <p> [PDF_B] 1st Page </p>
    <div style = 'page-break-after: always;' ></div>
    <p> [PDF_B] 2nd Page</p>";

var renderer = new ChromePdfRenderer();

var pdfdoc_a = renderer.RenderHtmlAsPdf(html_a);
var pdfdoc_b = renderer.RenderHtmlAsPdf(html_b);

// Four paged PDF
var merged = PdfDocument.Merge(pdfdoc_a, pdfdoc_b);
merged.SaveAs("Merged.pdf");

using IronPdf;

// Two paged PDF
const string html_a =
    @"<p> [PDF_A] </p>
    <p> [PDF_A] 1st Page </p>
    <div style = 'page-break-after: always;' ></div>
    <p> [PDF_A] 2nd Page</p>";

// Two paged PDF
const string html_b =
    @"<p> [PDF_B] </p>
    <p> [PDF_B] 1st Page </p>
    <div style = 'page-break-after: always;' ></div>
    <p> [PDF_B] 2nd Page</p>";

var renderer = new ChromePdfRenderer();

var pdfdoc_a = renderer.RenderHtmlAsPdf(html_a);
var pdfdoc_b = renderer.RenderHtmlAsPdf(html_b);

// Four paged PDF
var merged = PdfDocument.Merge(pdfdoc_a, pdfdoc_b);
merged.SaveAs("Merged.pdf");

Imports IronPdf

' Two paged PDF
Private Const html_a As String = "<p> [PDF_A] </p>
    <p> [PDF_A] 1st Page </p>
    <div style = 'page-break-after: always;' ></div>
    <p> [PDF_A] 2nd Page</p>"

' Two paged PDF
Private Const html_b As String = "<p> [PDF_B] </p>
    <p> [PDF_B] 1st Page </p>
    <div style = 'page-break-after: always;' ></div>
    <p> [PDF_B] 2nd Page</p>"

Private renderer = New ChromePdfRenderer()

Private pdfdoc_a = renderer.RenderHtmlAsPdf(html_a)
Private pdfdoc_b = renderer.RenderHtmlAsPdf(html_b)

' Four paged PDF
Private merged = PdfDocument.Merge(pdfdoc_a, pdfdoc_b)
merged.SaveAs("Merged.pdf")

Imports IronPdf

' Two paged PDF
Private Const html_a As String = "<p> [PDF_A] </p>
    <p> [PDF_A] 1st Page </p>
    <div style = 'page-break-after: always;' ></div>
    <p> [PDF_A] 2nd Page</p>"

' Two paged PDF
Private Const html_b As String = "<p> [PDF_B] </p>
    <p> [PDF_B] 1st Page </p>
    <div style = 'page-break-after: always;' ></div>
    <p> [PDF_B] 2nd Page</p>"

Private renderer = New ChromePdfRenderer()

Private pdfdoc_a = renderer.RenderHtmlAsPdf(html_a)
Private pdfdoc_b = renderer.RenderHtmlAsPdf(html_b)

' Four paged PDF
Private merged = PdfDocument.Merge(pdfdoc_a, pdfdoc_b)
merged.SaveAs("Merged.pdf")

This merging functionality is essential when combining documents from different sources or when you need to add, copy, or delete PDF pages. The resulting PDF 1.7 document ensures all features from both source documents are preserved.

Why Does IronPDF Use Version 1.7 for Merged Documents?

IronPDF generated a 1.7 version PDF by merging the two PDFs. This ensures:

1. Universal Compatibility: PDF 1.7 is supported by all modern PDF readers and browsers
2. Feature Preservation: All advanced features from source documents are maintained
3. Future-Proofing: As the ISO standard, PDF 1.7 ensures long-term document accessibility
4. Enhanced Security: Support for advanced PDF permissions and passwords

My favorite library of this kind is IronPDF. It allows for fast and efficient manipulation of PDF files. It also has many valuable features, like exporting to PDF/A format and digitally signing PDF documents.

Milan Jovanovic

Microsoft MVP

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IronOCR means we can save $40,000 annually from manual processing, while enhancing productivity and freeing up resources for high-impact tasks. I would highly recommend it.

Brent Matzelle

Chief Technology Officer, OPYN

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The IronSuite play a crucial role in our operations. These are tools that increase efficiencies across the business including creating floor plans and improving inventory management.

David Jones

Lead Software Engineer, Agorus Build

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Advanced PDF Version Considerations

When working with PDF versions in IronPDF, several factors influence automatic version selection:

Content Complexity

Simple HTML with basic text and images typically results in PDF 1.4, while documents containing JavaScript, forms, or multimedia content may trigger higher versions. When executing custom JavaScript in your PDFs, IronPDF may select a higher version to support these interactive features.

Feature Requirements

Certain features require specific PDF versions:

• PDF 1.4: Basic transparency, font embedding
• PDF 1.5: Layers, object streams
• PDF 1.6: OpenType fonts, 3D annotations
• PDF 1.7: Enhanced security, package/portfolio features

Compliance and Standards

For archival purposes, you might need specific versions. IronPDF supports creating PDF/A format documents for long-term preservation, which have their own version requirements based on the PDF/A level chosen.

Performance Optimization

Different PDF versions have varying file sizes and processing requirements. PDF 1.4 documents are generally smaller and process faster, making them ideal for high-volume applications. Learn more about PDF compression techniques to optimize your documents.

By understanding these version differences and letting IronPDF handle selection automatically, you ensure your PDFs maintain the perfect balance between compatibility, features, and performance for your specific use case.

Curtis Chau

Chat with engineering team now

Technical Writer

Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.

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