Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires symfony/swiftmailer-bundle ^3.0 -> satisfiable by symfony/swiftmailer-bundle[v3.0.0, ..., v3.5.4]. - symfony/swiftmailer-bundle[v3.0.0, ..., v3.0.4] require symfony/dependency-injection ~2.7|~3.0 -> found symfony/dependency-injection[v2.7.0, ..., v2.8.52, v3.0.0, ..., v3.4.47] but these were not loaded, likely because it conflicts with another require. - symfony/swiftmailer-bundle[v3.1.0, ..., v3.1.4] require symfony/dependency-injection ~2.7|~3.4|~4.0 -> found symfony/dependency-injection[v2.7.0, ..., v2.8.52, v3.4.0, ..., v3.4.47, v4.0.0, ..., v4.4.49] but these were not loaded, likely because it conflicts with another require. - symfony/swiftmailer-bundle[v3.1.5, ..., v3.2.8] require symfony/dependency-injection ~2.7|~3.3|~4.0 -> found symfony/dependency-injection[v2.7.0, ..., v2.8.52, v3.3.0, ..., v3.4.47, v4.0.0, ..., v4.4.49] but these were not loaded, likely because it conflicts with another require. - symfony/swiftmailer-bundle[v3.3.0, ..., v3.3.1] require symfony/dependency-injection ^3.4|^4.0|^5.0 -> found symfony/dependency-injection[v3.4.0, ..., v3.4.47, v4.0.0, ..., v4.4.49, v5.0.0, ..., v5.4.48] but these were not loaded, likely because it conflicts with another require. - symfony/swiftmailer-bundle v3.4.0 requires symfony/dependency-injection ^4.3.8|^5.0 -> found symfony/dependency-injection[v4.3.8, ..., v4.4.49, v5.0.0, ..., v5.4.48] but these were not loaded, likely because it conflicts with another require. - symfony/swiftmailer-bundle[v3.5.0, ..., v3.5.4] require symfony/dependency-injection ^4.4|^5.0 -> found symfony/dependency-injection[v4.4.0, ..., v4.4.49, v5.0.0, ..., v5.4.48] but these were not loaded, likely because it conflicts with another require. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.

Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires symfony/swiftmailer-bundle ^3.0 -> satisfiable by symfony/swiftmailer-bundle[v3.0.0, ..., v3.5.4]. - symfony/swiftmailer-bundle[v3.0.0, ..., v3.0.4] require symfony/dependency-injection ~2.7|~3.0 -> found symfony/dependency-injection[v2.7.0, ..., v2.8.52, v3.0.0, ..., v3.4.47] but these were not loaded, likely because it conflicts with another require. - symfony/swiftmailer-bundle[v3.1.0, ..., v3.1.4] require symfony/dependency-injection ~2.7|~3.4|~4.0 -> found symfony/dependency-injection[v2.7.0, ..., v2.8.52, v3.4.0, ..., v3.4.47, v4.0.0, ..., v4.4.49] but these were not loaded, likely because it conflicts with another require. - symfony/swiftmailer-bundle[v3.1.5, ..., v3.2.8] require symfony/dependency-injection ~2.7|~3.3|~4.0 -> found symfony/dependency-injection[v2.7.0, ..., v2.8.52, v3.3.0, ..., v3.4.47, v4.0.0, ..., v4.4.49] but these were not loaded, likely because it conflicts with another require. - symfony/swiftmailer-bundle[v3.3.0, ..., v3.3.1] require symfony/dependency-injection ^3.4|^4.0|^5.0 -> found symfony/dependency-injection[v3.4.0, ..., v3.4.47, v4.0.0, ..., v4.4.49, v5.0.0, ..., v5.4.48] but these were not loaded, likely because it conflicts with another require. - symfony/swiftmailer-bundle v3.4.0 requires symfony/dependency-injection ^4.3.8|^5.0 -> found symfony/dependency-injection[v4.3.8, ..., v4.4.49, v5.0.0, ..., v5.4.48] but these were not loaded, likely because it conflicts with another require. - symfony/swiftmailer-bundle[v3.5.0, ..., v3.5.4] require symfony/dependency-injection ^4.4|^5.0 -> found symfony/dependency-injection[v4.4.0, ..., v4.4.49, v5.0.0, ..., v5.4.48] but these were not loaded, likely because it conflicts with another require. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.